BAGHDAD/WASHINGTON－Iraq's Parliament called on Sunday for the United States and other foreign troops to leave as a backlash grows against the US killing of a top Iranian general, and US President Donald Trump warned Iraq that he would levy punishing sanctions if it expelled US troops.

Leading Iranian General Qasem Soleimani was killed on Friday in a US drone strike on his convoy at Baghdad airport, an attack that carried US-Iranian hostilities into uncharted waters.

Trump threatened sanctions against Iraq and said that if US troops were required to leave the country, Iraq's government would have to pay Washington for the cost of a "very extraordinarily expensive" air base there.

He said if Iraq asked US forces to leave on an unfriendly basis, "we will charge them sanctions like they've never seen before ever. It'll make Iranian sanctions look somewhat tame".

Trump's warning came hours after Iraq's Parliament on Sunday passed a resolution requiring the government to end the presence of foreign forces in Iraq, and prevent them from using Iraqi air space and waterways.

In addition, the Iraqi government should "file a complaint against the US for its violations and grave breaches of Iraqi sovereignty and security", the Parliament said in a statement.

The Iraqi Parliament's move reflected the fears of many in Iraq that Friday's strike could engulf them in another war between two bigger powers long at odds in Iraq and across the region.

While such resolutions are not binding on the government, this one is likely to be heeded: Iraqi caretaker Prime Minister Adel Abdul Mahdi had earlier called on the Parliament to end the presence of foreign troops as soon as possible.

Iran and the US have been competing for clout in Iraq since the US-led invasion in 2003 that toppled Saddam Hussein.

Vote on foreign troops

Before Trump's comments to reporters, a US State Department spokeswoman said Washington was waiting for clarification of the legal nature and impact of the resolution, and strongly urged Iraqi leaders to reconsider the importance of the two nations' ongoing economic and security relationship.

Nearly 5,000 US troops remain in Iraq, most in an advisory role.

Abdul Mahdi said that despite the "internal and external difficulties" the country might face, canceling its request for help from US-led coalition military forces "remains best for Iraq on principle and practically".

He said he had been scheduled to meet Soleimani the day he was killed, and that the general had been due to deliver an Iranian response to a message from Saudi Arabia that Abdul Mahdi had earlier passed to Teheran. Sunni Muslim Saudi Arabia and Shiite Iran had been about to "reach a breakthrough over the situation in Iraq and the region", Abdul Mahdi said.

Despite decades of US-Iran enmity, Iran-backed militias and US troops fought side by side during Iraq's 2014-17 war against the Islamic State terror group, their common enemy. Iraqi militia leader Abu Mahdi al-Muhandis was also killed in Friday's strike.

Sunday's parliamentary resolution was passed by overwhelmingly Shiite lawmakers, as the special session was boycotted by most Sunni Muslim and Kurdish lawmakers.

One Sunni member of Parliament said both groups feared that kicking out US-led forces would leave Iraq vulnerable to insurgents, undermine security and heighten the power of Iran-backed Shiite militias.

Arab League Secretary General Ahmed Aboul-Gheit expressed on Sunday his growing concern about the recent developments in Iraq, in a statement on behalf of the Cairo-based, pan-Arab body.

"The region is in a dire need of calm not escalation, and of settling conflicts not igniting and sustaining them," said the statement.

"The developments in recent days show the size of foreign interventions in Arab affairs and their high political, security and economic costs."