Strange bedfellows: Iran, US to cooperate against Sunni jihadists in Iraq?
"We have said that all countries must unite in combating terrorism. But right now regarding Iraq we have not seen the Americans taking a decision yet," Rouhani said at a press conference on Saturday.
Asked if Tehran would work with its old adversary the United States in tackling advances by Sunni insurgents in Iraq, he replied, "We can think about if we see America starts confronting the terrorist groups in Iraq or elsewhere."
Rouhani denied previous reports that Iran had already sent troops into Iraq to aid government forces, saying any such move would be contingent on Baghdad’s approval.
"No specific request has been put forward, but we are prepared to help – within the frameworks of international regulations – if there is a request," he said.
Iran has already sent a Major General from the Revolutionary Guard to meet with leaders in the Iraqi capital.
US President Barack Obama has so far ruled out putting American troops on the ground in Iraq, though Washington is seriously considering other options, including deploying air or naval forces to carry out air strikes against militant positions.
"We will not be sending US troops back into combat in Iraq, but I have asked my national security team to prepare a range of other options that could help support Iraqi security forces," Obama said on Friday.
The White House is expected to make a decision in the coming days, though Obama stressed that Iraq was ultimately responsible for its own security.
“The United States will do our part, but ultimately it's up to the Iraqis as a sovereign nation to solve their problems," Obama said. "We can't do it for them."
The Sunni insurgents – from the Islamic State in Iraq and the Levant (ISIL) – have managed to seize the Iraqi cities of Mosul and Tikrit with an estimated 7,000 strong force. On Friday, Shia fighters attempted to counter ISIS momentum near Muqdadiya, just 80km (50 miles) from Baghdad's city limits.
The UN said ISIS forces have carried out summary executions and rapes in as it battles to take over the country.
The hyper-fundamentalist group has alienated Al-Qaeda with its tactics, which include publicly crucifying and beheading those who violate their strict religious interpretations.
Iraq came under the influence of a Shia-majority government after the US-led invasion toppled Saddam Hussein's Sunni-dominated regime in 2003. Since the withdrawal of US troops in 2011, sectarian tensions boiled over, resulting in Sunni insurgents increasingly waging war against the central government.
Iran, a strict Shia-theocracy since 1979, Iran has built close political and economic ties with and does not want to see a Sunni-caliphate established on its borders.