Iraq's foreign minister has asked the US to launch air attacks on Sunni rebels to put down a week-long rebellion by fighters led by the Islamic State of Iraq and the Levant.

Hoshyar Zebari told a news conference on Wednesday in Jeddah, Saudi Arabia, that a request had been made "to break the morale" of ISIL fighters.

The statement came as Iraqi security forces battled rebels at the country's main oil refinery and claimed to regain partial control of a city near the Syrian border.

General Martin Dempsey, the top US military commander, confirmed the request during a Senate sub-committee hearing.

"We have a request from the Iraqi government for air power," said Dempsey. "It is in our national security interest to counter ISIL wherever we find them."

Meanwhile, US President Barack Obama told Congressional leaders he didn't not need congress' approval for any action in Iraq, a leading Senate Republican said.

After a meeting between the president and senior members of Congress, Senator Mitch McConnell told reporters the president "indicated he didn't feel he had any need for authority from us for steps that he might take."

White House officials have suggested Obama may be able to act on his own as the Iraq government has requested US military assistance.

Earlier, Nouri al-Maliki, the Iraqi prime minister, said the government had "started our counter-offensive, regaining the initiative and striking back".

Maliki's relatively upbeat assessment came as the military claimed its forces regained parts of the strategic city of Tal Afar near the Syrian border, which ISIL fighters captured on Monday.