WASHINGTON, Jan. 5 (Xinhua) -- U.S. President Donald Trump on Sunday threatened to impose harsh sanctions on Iraq after the war-torn country's parliament passed a resolution urging the government to expel foreign troops.

"If they do ask us to leave, if we don't do it in a very friendly basis, we will charge them sanctions like they've never seen before ever. It'll make Iranian sanctions look somewhat tame," Trump told reporters on Air Force One.

"We have a very extraordinarily expensive air base that's there. It costs billions of dollars to build ... We're not leaving unless they pay us back for it," he added.

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

Iraqi caretaker Prime Minister Adel Abdul Mahdi attended the televised parliament session and addressed the lawmakers, saying "the departure of the U.S. forces from Iraq will be in the benefit of Iraq and the United States, especially after the latest developments."

The U.S. State Department said in a statement on Sunday that America is "disappointed" by the action taken by the Iraqi parliament.

"We strongly urge Iraqi leaders to reconsider the importance of the ongoing economic and security relationship between the two countries and the continued presence of the Global Coalition to Defeat ISIS (the Islamic State)," the statement said.

The Iraqi parliament session came two days after a U.S. drone strike on a convoy near Baghdad International Airport killed Qassem Soleimani, commander of the Quds Force of Iran's Islamic Revolution Guards Corps, and Abu Mahdi al-Muhandis, deputy chief of Iraq's paramilitary Hashd Shaabi forces.

Over 5,000 U.S. troops have been deployed in Iraq to support the Iraqi forces in the battles against the IS militants, mainly providing training and advising to the Iraqi forces.