BAGHDAD (Reuters) - Iraqi Prime Minister Haider al-Abadi faced calls on Tuesday to take measures ranging from an economic blockade to military action after Kurds voted in a referendum in support of independence. But he will need to proceed cautiously. Abadi has been trying to unite Iraq since he took office, focusing mainly on sectarian hostilities between Shi ites and Sunnis, which had triggered a civil war, and Islamic State militants who seized a third of his country before their defeat. The Shi ite-led Baghdad government and the Kurdish region in the north have struggled for years to resolve differences over oil and other sensitive issues. But Monday s vote, which is likely to lead to a breakaway state that has been the dream of generations of Kurds, has ratcheted up tensions, posing one of the biggest challenges to Abadi as he tries to keep Iraq together. The Iraqi government ruled out talks on possible secession for Kurdish-held parts of northern Iraq on Tuesday after projections by the Kurdish Rudaw TV channel showed support for a split could be over 90 percent. Neighboring Iran and Turkey also fiercely oppose independence in the north. They say it will cause regional chaos, and they also fear secession will encourage their own restive Kurdish populations to press for self-determination. Now Abadi s Shi ite constituency, as well as Sunni Arabs opposed to Kurdish independence, will be pressing him to take firm action. Disputed areas such as the multi-ethnic oil city of Kirkuk could be a flashpoint for widespread instability.  Kurds have gone too far and government must show them a tougher face. Government forces must go to maintain peace in Kirkuk and all other areas Kurds try to control by force,  said Mohammed Tamim, an Arab Sunni lawmaker from Kirkuk       Parliament has authorized Abadi to safeguard Iraqi unity and such a mandate allows him to send troops.  Mobilizing government troops may not be so easy. The army has spent years fighting Islamic State and the recent battle to drive the group out of Mosul has left many of Iraq s formations exhausted. Those troops that can fight are engaged in operations against Islamic State militants west of Kirkuk and near the Syrian border.  Another option would be to turn to Iranian-backed paramilitary groups. Some, like Asaib ahl al-Haq, have already threatened to march on Kirkuk. Tehran supports Shi ite Muslim groups that have been prominent in Iraq since the U.S.-led invasion that toppled Saddam Hussein in 2003.  Abadi, as the commander of armed forces, must switch the needle of the fighting compass toward Kirkuk,  said Hashim al-Mouasawi, a spokesman for the Shi ite Nujaba group, which has about 10,000 fighters and is loyal to Iran.  We are fully prepared to answer Abadi s orders to liberate Kirkuk and the oilfields from the separatist militias  control before it s too late. We will fight to safeguard the prestige of the state.  While the use of these paramilitary groups against the Kurds would spare the army from having to fight against fellow Iraqis, there are risks for Abadi. Tensions are already high between Kurdish peshmerga fighters and Shi ite paramilitary forces, even though they cooperated in the fight against Islamic State. Now that Islamic State has largely been removed from strategic areas, the ethnic and sectarian battle for land and influence that has dogged Iraq could complicate efforts to create harmony among its many sects and communities. If the Shi ite paramilitaries and Kurds clash, it will mean all-out war between two of the best fighting forces in Iraq, a U.S. ally and OPEC oil producer with an economy shattered by conflict. Vahal Ali, a spokesman for Masoud Barzani, president of the Kurdistan Regional Government, said the Kurds would not take further steps toward independence without pursuing peaceful negotiations with the Baghdad government. But, he added, Kurds did not have endless patience.  If we are attacked we will defend ourselves,  he said.  We are not breaking any laws. The Kurdish people were given a chance to vote and they did.  For its part, the Iraqi government gave the KRG three days to hand over  control of its airports in order to avoid an international air embargo, Abadi said, according to state TV. Baghdad asked foreign countries to stop flights to the international airports of Erbil and Sulaimaniya, in KRG territory, but only Iran complied.   Lawmakers called on Abadi to apply economic pressure on the Kurds, who suffered under Saddam for decades and then began building a semi-autonomous zone in the north after his fall. One possibility is a blockade of Kurdish areas, something that Vahal Ali said would also harm the Baghdad government.  The Government must take tough measures to prevent the Kurdish leaders from going too far,  said Shi ite lawmaker Ammar Tuma. He called for  shutting down exits and entrances, controlling the border crossings, chasing the funds Kurdish leaders generated from illegal oil sales, and finally deploying Iraqi forces in areas they try to control by force.  Kurdish oil sales without the consent of the government have angered Iraqi leaders. But placing an economic stranglehold on the Kurds may have only limited success for Baghdad if Turkey continues to trade with the north. Turkey has long been northern Iraq s main link to the outside world and the KRG exports hundreds of thousands of barrels of oil per day to world markets via Turkey. Turkish President Tayyip Erdogan said Iraqi Kurds would go hungry if his country halts the flow of goods and oil across the border with northern Iraq. And while it sees the referendum as a grave matter for its own national security, Turkey has built good relations with Barzani s Kurdish administration. Iraq, including the Kurdish region, was Turkey s third-largest export market in 2016. Erdogan has repeatedly threatened economic sanctions against the Kurds in response to the referendum, but he has so far given few specifics. 