ALGIERS , Algeria -LRB- CNN -RRB- -- Rescuers are sifting through the rubble of the United Nations headquarters in Algiers hoping to find survivors after a powerful bomb ripped off the building 's facade and leveled nearby U.N. offices . Rescuers and bomb experts search for survivors in the rubble of a destroyed building . It was one of two suspected car bombs that struck Algiers within 10 minutes of each other . The death toll is unclear : the official government count is at least 26 , but hospital sources in Algiers told CNN affiliate BFM-TV that 76 people were killed in the two blasts . A statement from the United Nations said 45 people were reported killed . Algerian Interior Minister Noureddine Yazid Zerhouni blamed a militant Islamic group with ties to al Qaeda for the attacks , which also targeted a building housing Algeria 's Constitutional Council and Supreme Court . In a posting on an Islamist Web site , the group al Qaeda Islamic Maghreb claimed responsibility . CNN could not immediately corroborate that claim , but the Web site is known to carry messages , claims and videos from al Qaeda and other militant groups . In the posting , the bombers were identified as Sheikh Ibrahim Abu Othman and Abdel Rahman Abu Abdel Nasser al-Asimi . It said two trucks were filled with `` no less than 800 kg -LRB- 1,763 pounds -RRB- of explosives . '' The group called the operation `` another successful conquest and a second epic that the knights of faith have dictated with their blood , defending the wounded Islamic nation and in defiance to the Crusaders and their agents , the slaves of America and the sons of France . '' At least 10 U.N. staffers were among those killed , according to U.N. spokeswoman Marie Okabe . The offices of the UN High Commissioner for Refugees -- located across the street from the U.N. headquarters -- were leveled by a blast that struck about 9:30 a.m. -LRB- 3:30 a.m. ET -RRB- Tuesday . `` Our offices are basically destroyed now , nothing works , '' UNHCR spokesman Ron Redmond said from its Geneva headquarters . Watch his full interview He said rescuers are working into the night trying to get to the trapped U.N. workers . `` It 's a very serious situation still with the U.N. in Algiers , '' he said . In a strongly worded statement , U.N. Secretary-General Ban Ki-moon condemned what he called `` an abjectly cowardly strike against civilian officials serving humanity 's highest ideals under the U.N. banner . '' `` The perpetrators of these crimes will not escape the strongest possible condemnation -- and ultimate punishment -- by Algerian authorities and the international community , '' Ban said in the written statement . He said he has sent senior advisers and other top U.N. officials to head to Algiers to assist in the investigation and rescue effort . Most of those killed in the coordinated attacks were victims of the first suspected car bombing near the Constitutional Council -- which oversees elections -- and Supreme Court in the Algiers neighborhood of Ben Aknoun , according to the state-run Algeria Press Agency . That blast struck a bus outside the targeted building , killing many of those on board , the news agency reported . One man said he heard the first blast then the second exploded in front of him . `` I saw the trees falling and the glass shattering in front of me . I had to run away from the car , '' he said . Zerhouni said the attack was the work of the Salafist Group for Preaching and Combat -LRB- GSPC -RRB- , the same group that took responsibility for an attack in April in downtown Algiers that killed 33 people . That group also uses the name al Qaeda Islamic Maghreb after merging with al Qaeda earlier this year . It abandoned small-scale attacks in favor of headline-grabbing blasts after it joined with al Qaeda . CNN International Security Correspondent Paula Newton said the merger combined the expertise of Algerian guerrillas with the operational ability of al Qaeda in North Africa , enabling the group to penetrate the usually extensive security in high-profile areas of Algiers . She said the group 's goal is to destabilize countries like Algeria , Morocco and Tunisia , which it sees as enemies of the Islamic state . Zerhouni said police interrogations of GSPC members arrested in the wake of the April attack revealed that Algeria 's Constitutional Council and Supreme Court were on a list of GSPC targets . Algeria , which has a population of 33 million , is still recovering from more than a decade of violence that began after the military government called a halt to elections which an Islamist party was poised to win . Tens of thousands of people died in the unrest . Although the country has remained relatively peaceful , recent terrorist attacks have raised fears of a slide back to violence . E-mail to a friend