GRABOVO, Ukraine — As rescue teams slowly converged on the grisly scene of the downing of a Malaysia Airlines jet, the Russian Defense Ministry on Friday denied any involvement in the missile strike that Ukrainian officials said ripped the Boeing 777 from the sky on Thursday, and many began questioning why the airline had chosen to fly a civilian jet over a combat zone.

The crash site was still unsecured by midday Friday, raising questions about who controlled the flight data recorder, cockpit voice recorder and other onboard devices that could help determine exactly how the crash occurred. Rebel spokesmen said they had recovered most of the devices, but it was unclear when and to whom they would turn them over for investigation.


Russian officials were adamant that they had nothing to do with the disaster, continuing to point fingers at the Ukrainian government and military. “In view of various types of speculation concerning operations of the Russian armed forces in the areas bordering Ukraine, we affirm that the anti-aircraft means of the Russian armed forces did not operate in that region on July 17,’’ the Defense Ministry said in a statement posted on its website.

The statement also said its air force was not flying within Russia in the areas bordering Donetsk on Thursday.

Officials in the United States confirmed late Thursday that Flight 17, with 298 people aboard, had been shot down over Grabovo, Ukraine, by what they described as a Russian-made antiaircraft missile. Fighting in eastern Ukraine between the Ukrainian military and pro-Russian separatists has been marked by the successful use of missiles against aircraft at higher and higher altitudes. The downing on Thursday of Flight 17, struck at 33,000 feet, was the first at cruising altitude for modern commercial jets, however.

The Russian defense statement noted that units of the Ukrainian Army possessed the BUK M1 air defense missile launchers that officials said were most likely responsible for bringing the jetliner down. Much of the speculation surrounding the crash has focused on that system, particularly since the pro-Russian separatist forces in eastern Ukraine bragged on social media in late June that they had taken possession of a BUK system after capturing a Ukrainian military base.


The crash remained the subject of intense debate in the small Ukrainian town of Grabovo, as residents tried to come to grips with what had unfolded in the fields where they work, just yards from their homes.

Two villagers said they had seen the flash of a rocket in the sky around the time the plane went down. Victor, who said he was too afraid to give his last name, said that he had been in his garden at the time and that he had seen “the light coming from a rocket.’’

He said it had come from the direction of Snizhne, a city where the Ukrainian military has been bombing rebel positions frequently for more than a week. “It was a rocket, I’m sure of it,’’ he said.

The other villager, Sergei, 15, who also did not want to give his last name, said he had been swimming in a nearby river when he saw what appeared to be a rocket being launched into the sky. He said he then jumped out of the water, hopped on his motorbike and sped home.

As a cloudy dawn came, the full horror of the crash site was on display. Small white pieces of cloth dotted the grassy farmland, marking the spots of bodies.

Four rebels in fatigues were wandering through the ruins, looking through people’s belongings and riffling through guidebooks and bags.

When asked who was responsible for the crash, they looked incredulous and said that it had of course been the Ukrainian military.


“This wasn’t ours,’’ said a rebel who identified himself only as Alexei, standing looking at an overhead bin in the grass with a rifle over his shoulder. “Why would we do this? We’re not animals.’’

The plane appeared to have broken apart at a great height as pieces were scattered across several miles of agricultural fields. The plane was full of fuel when it crashed and the fire near the engine was fierce, turning the twisted metal remains into molten pools that had hardened by morning.

“This is direct provocation of the EU and the U.S.,’’ said a rebel, Alexander Nikolaevich, who was walking along the road near the scene. “You see our weapons,’’ he said pointing to his aging gun. “We started to win the war and the fascists did this to stop us.’’

When asked if the fight would continue, he said, “a little bit.’’

In Malaysia, the heavily Muslim nation in Southeast Asia, people mourned on a holy Ramadan Friday, shocked at the sudden loss of a second Malaysia Airlines Boeing 777-200. Many began questioning why the plane was flying over a conflict in eastern Ukraine where increasingly powerful surface-to-air missiles were being used.

In a statement delivered before dawn in Kuala Lumpur, Prime Minister Najib Razak of Malaysia noted that the International Civil Aviation Organization had declared the airspace safe and that the International Air Transport Association had not restricted travel there. “We must — and we will — find out precisely what happened to this flight,’’ he said.

Peppered with questions about the aircraft’s route during a news conference late Thursday at a Kuala Lumpur airport hotel, Liow Tiong Lai, the Malaysian transport minister, said the aircraft had been following a safe route that Malaysia Airlines had used for many years and that was still used by most Asian airlines and by many European airlines, including on the day of the crash. “During that period of time, there are also many other aircraft using the same route,’’ he said.

European and Ukrainian air traffic controllers had continued to route civil flights over the contested area even as the fighting worsened — and even as flights directed by Russian air traffic controllers had apparently started to avoid it.

Ukrainian intelligence has pointed to a fighter named Igor Bezler, the militia leader in the eastern town of Gorlovka, as saying in an intercepted phone call that his men had “shot down a plane’’ on Thursday. Several assassinations are believed to have happened under Bezler’s watch soon after his forces took Gorlovka, and he took responsibility for killing a number of Ukrainian militiamen in the town of Volnovakha some weeks ago.

According to Russian Internet sources, Bezler was born in 1965 in Crimea, and studied in Russia. He served in the Russian military but moved back to Ukraine in 2003, where he began to work as the head of security for a factory in Gorlovka. Biographies also note that he had worked in a company that performed burial services but was fired in 2012. He has been wanted by the Ukrainian authorities since April 2014.

Bezler’s nom de guerre is Bes, which in Russian sounds like the first syllable of his last name, but also means demon. There are rumors that Bezler does not get along with other militia leaders, and that he has had street battles with the Vostok Battalion, though rebels have dismissed those allegations.

In a slickly produced video called “Heroes of Novorossii,’’ the name of the self-declared insurgent region, Bezler was shown wearing a light blue beret. In a recent interview with the Russian news agency RIA Novosti, he claimed to be holding 14 Ukrainian soldiers hostage and said that the Ukrainian military had fallen apart, “much like the condition of the Russian military in the early 1990s.’’

In the interview, Bezler said he was a Russian passport holder but had a residency permit in Ukraine. He said he sang the national anthem of the Soviet Union every morning, and usually went to bed around 10:30 p.m. He confirmed that he had worked as head of security for the Gorlovka factory, and claimed that he was fired from the burial services company over a fight with the local mayor who he said was demanding bribes.

Peter Marosszeky, a longtime aircraft engineer and former senior executive at Qantas, PanAm and American Airlines who advised Boeing on the development of the 777 aircraft, said in a telephone interview that the 777-200 had an extremely long range and would have enough fuel to divert around a dangerous area during a 12-hour flight if the pilots chose to do so. But he said that airlines have typically not worried until now about surface-to-air missiles reaching planes at cruising altitude, because only a very large missile with a lot of fuel could ascend such a distance.

Marosszeky expressed skepticism that militiamen could readily fire such a large missile without training as well as cooperation from whoever owned or manufactured the missile. “You’ve got to have special codes and so forth to operate these things,’’ he said.

Questions about why commercial air traffic was continuing in the area — and about when air traffic should be stopped over similar areas of fighting in the future — could prove difficult to answer. The investigation into the loss of Flight 17 is laden with potential disputes over sovereignty.

Mark A. Dombroff, a partner focusing on the aviation industry at McKenna Long & Aldridge, a national law firm in the United States, said that legal precedents indicated that if a plane is downed by military action, the lead country in the investigation is the one over whose territory the plane was shot down. That appears to be Ukraine in this case — but the rebels in eastern Ukraine, where the plane crashed, do not recognize the leadership in Kiev and may try to claim the lead role in the investigation.

“One of the most complicated factors is getting investigators on the ground in hostile territory,’’ Dombroff said.

Ukraine or the rebels — or both — could decide to transfer leadership of the crash investigation either to the country of registry of the aircraft, which would be Malaysia, or to the country of manufacture of the Boeing 777, which would be the United States.

Alexander Borodai, the prime minister of the self-declared Donetsk People’s Republic, the main separatist organization, said the group was setting up a committee to investigate the crash, the news agency Interfax reported. Russian government officials continued to emphasize the official line Friday that the investigation was under Ukrainian jurisdiction.

Leading a crash investigation is in some ways a formality for developing countries, as most of the world’s investigators with crash experience tend to come from countries that manufacture aircraft and certify their airworthiness. Russia’s proximity to the crash site, close ties to the rebels and extensive aviation experience means that it could try to play a sizable advisory role, particularly if the rebels follow through on reported plans to locate the flight data recorders and send them to Moscow.

The crash is another setback for Malaysia Airlines, which has already been struggling to recover from the loss of Flight 370, which vanished on March 8 during a red-eye flight from Kuala Lumpur to Beijing.

The enduring mystery over Flight 370 has already severely hurt demand for Malaysia Airlines tickets, forcing the airline to offer budget carrier prices even though it bears the costs of a full-service airline.

Both Korean Air Lines and Asiana Airlines have confirmed that they have not flown planes through Ukrainian airspace since March 3.

“We detoured our flight because of political instability there,’’ said Lee Hyo-min, a spokeswoman at Asiana, which had been flying a cargo plane through Ukrainian airspace once a week from Brussels to Incheon, South Korea, until that point.

Korean Air Lines had been sending 42 passenger and cargo flights per month through Ukrainian airspace, but those flights had been rerouted, beginning on March 3, company officials said.

Civilian jetliners have been shot down on a few previous occasions, including by the United States. The USS Vincennes used a pair of surface-to-air missiles in 1988 to destroy Iran Air Flight 655, killing 290 people, when the ship’s radar operators mistakenly concluded that the plane was descending toward them in a possible attack. A later review found that the jetliner was ascending at the time. It had been following a flight path that Iranian F-14 fighter jets had used in the preceding days to approach the American vessel, before veering away when warned by radio.

In 1983, a Russian Air Force fighter jet downed a Korean Air Lines flight that was traveling from New York City to Seoul by way of Anchorage, after the plane wandered off course.

Chinese fighters shot down a Cathay Pacific airliner in 1954 off the coast of Hainan Island, southern China, in an incident that had its roots in a civil war. China’s explanation at the time was that it had feared the Cathay Pacific plane was a military aircraft belonging to the nationalists on Taiwan, who had lost the civil war in mainland China but who were technically still at war.