US lawmakers clashed Monday over intelligence on Iran, with an ally of President Donald Trump accusing Tehran of provocations that could draw a military response, ahead of a classified briefing on the tensions.

Acting Defense Secretary Patrick Shanahan and General Joseph Dunford, the chairman of the joint chiefs of staff, were set to head to the US Capitol yesterday to apprise lawmakers from both chambers on the latest developments, an administration official said.

Senior officials already briefed a key group of eight lawmakers on Thursday. Senator Lindsey Graham, a Republican who has closely aligned himself with Trump, said he received his own briefing Monday from National Security Advisor John Bolton, a longtime hawk who called for an attack on Iran before taking his White House job.

"It is clear that over the last several weeks Iran has attacked pipelines and ships of other nations and created threat streams against American interests in Iraq," Graham tweeted.

"If the Iranian threats against American personnel and interests are activated we must deliver an overwhelming military response."

A Democratic lawmaker, Representative Ruben Gallego of Arizona, quickly challenged Graham and said he had seen the same intelligence.

"That is not what is being said. This is total information bias to draw the conclusion he wants for himself and the media," Gallego tweeted.

Meanwhile, Iranian President Hassan Rouhani rejected any talks with the United States and yesterday called on the government to be given more power to run the sanctions-hit economy in an "economic war".

United Nations voiced concern on Monday about increasingly bellicose rhetoric between the United States and Iran and called on them to dial down their remarks.