US President Donald Trump says American troops should not leave Iraq unless Baghdad pays for “the money we put in” the country over the past several years, defying calls by Iraqi officials for US troops to withdraw.

“If we leave ... you have to pay us for the money we put in," Trump said Friday in an interview with Fox News at the White House.

When host Laura Ingraham asked how Trump planned to collect money from Iraq, the president said: "Well, we have a lot of their money right now. We have a lot of their money. We have $35 billion of their money right now sitting in an account. And I think they’ll agree to pay. I think they’ll agree to pay. Otherwise, we’ll stay there."

"We built one of the world's most expensive airport facilities, anywhere in the world," Trump told Ingraham. "I mean, I wish we had it in New York. I wish we had it in Washington."

Trump had tweeted last week: "The United States has paid Iraq Billions of Dollars a year, for many years.

Earlier this week, Iraqi caretaker Prime Minister Adil Abdul-Mahdi called for American troops to leave the country after the country’s parliament approved a resolution that called for the expulsion of all foreign forces from Iraq.

The vote came two days after the US military - acting on Trump’s order - launched a drone strike on top Iranian General Qassem Soleimani upon his arrival in the Iraqi capital at the invitation of the Baghdad government.

The attack also claimed the lives of senior Iraqi commander Abu Mahdi al-Muhandis and a number of their companions.

Iran subsequently conducted retaliatory missile strikes on two American bases in Iraq.

The US State Department said in a statement on Friday that Washington would not hold discussions with Baghdad regarding US troop withdrawal.

“At this time, any delegation sent to Iraq would be dedicated to discussing how to best recommit to our strategic partnership — not to discuss troop withdrawal, but our right, appropriate force posture in the Middle East,” State Department spokesperson Morgan Ortagus said.

“There does, however, need to be a conversation between the US and Iraqi governments not just regarding security, but about our financial, economic, and diplomatic partnership," she added.

The US, backed by the UK, invaded Iraq in 2003 under the pretext that the former regime of Saddam Hussein possessed weapons of mass destruction. No such weapons, however, were ever found in the country.

The invasion plunged Iraq into chaos and led to the rise of terrorist groups across the region.