Iraqi President Barham Salih said on Monday that U.S. President Donald Trump did not ask Iraq's permission for U.S. troops stationed there to "watch Iran."

Speaking at a forum in Baghdad, Salih was responding to a question about Trump's comments to CBS about how he would ask troops stationed in Iraq to "watch" Iran.

U.S. troops in Iraq are there as part of an agreement between the two countries with a specific mission of battling terrorism, Salih said, and they should stick to that.

Trump said it was important to keep a U.S. military presence in Iraq so that Washington can keep a close eye on Iran "because Iran is a real problem," according to a CBS interview broadcast on Sunday.

"Don't overburden Iraq with your own issues," Salih said. "The U.S. is a major power ... but do not pursue your own policy priorities. We live here."

Need for 'good relations'

Iraq is in a difficult position as tensions between its two biggest allies, the United States and Iran, increase.

"It is of fundamental interest for Iraq to have good relations with Iran" and other neighbouring countries, Salih said.

Trump announced in December that the 2,000 American troops in Syria would be withdrawn on the grounds that ISIS militants no longer pose a threat.

During a recent visit to Iraq, Trump said he had no plans to withdraw U.S. troops from Iraq.

In a report released Monday, the Pentagon inspector general said the Islamic State in Iraq and Syria remained an active insurgent group, and was regenerating functions and capabilities more quickly in Iraq than Syria.

"Absent sustained [counterterrorism] pressure, ISIS could likely resurge in Syria within six to 12 months and regain limited territory," the report said.

The report, citing information from U.S. Central Command, said ISIS would portray the withdrawal as a "victory" and conduct attacks on U.S. personnel as they withdraw.