US forces have come under repeated attack in Iraq and Syria since Hamas gunmen poured across the Gaza border on October 7, killing 1,400 people and seizing 239 hostages, according to Israeli officials.

Israel has in response unleashed a withering bombing campaign against the Gaza Strip that the Hamas-controlled health ministry said on Monday has killed 8,306 people.

"The attack on American bases in the region, especially in Iraq, is the result of wrong American policies in the region, which we hope it will correct," said Iran's foreign ministry spokesperson Nasser Kanani.

He said the attacks were carried out by groups against "the US presence in the region and seriously opposed to American support for the crimes of the Zionist regime (Israel)".

"You reap what you sow," he said, urging the United States to "stop" backing Israel.

Iran, which backs Hamas financially and militarily, has hailed the October 7 attacks as a "success" but denied any involvement.

Iran army's chief of staff Mohammad Bagheri on Monday said Hamas was "ready for an Israeli ground attack".

Earlier on Monday, some 200 protesters including Iranian Jews gathered at a synagogue in Tehran calling for a ceasefire and condemning "the massacre of children, women and defenceless people".

Iran has repeatedly warned of the expansion of the Hamas-Israel war to other parts of the region.

The White House has accused Tehran of "actively facilitating" attacks on US forces in the Middle East.

On Thursday, the US military said it had struck two facilities in eastern Syria used by Iran's Islamic Revolutionary Guard Corps and affiliated groups.

President Ebrahim Raisi has said Iran sees it as "its duty to support the resistance groups" but insisted that they "are independent in their opinion, decision and action".

The United States has around 2,500 troops in Iraq and some 900 in Syria as part of efforts to prevent a resurgence of the Islamic State extremist group.