Iran's supreme leader accused the United States on Sunday of trying to retake control of Iraq by exploiting sectarian rivalries, as Sunni insurgents drove towards Baghdad from new strongholds along the Syrian border.
Ayatollah Ali Khamenei's condemnation of US action came three days after President Barack Obama offered to send 300 military advisers to help the Iraqi government. Khamenei may want to block any US choice of a new prime minister after grumbling in Washington about Shi'ite premier Nuri al-Maliki.
The supreme leader did not mention the Iranian president's recent suggestion of cooperation with Shi'ite Tehran's old US adversary in defence of their mutual ally in Baghdad.
On Sunday, militants overran a second frontier post on the Syrian border, extending two weeks of swift territorial gains as the Islamic State of Iraq and the Levant (ISIL) pursues the goal of its own power base, a "caliphate" straddling both countries that has raised alarm across the Middle East and in the West.
"We are strongly opposed to US and other intervention in Iraq," IRNA news agency quoted Khamenei as saying. "We don't approve of it as we believe the Iraqi government, nation and religious authorities are capable of ending the sedition."
Some Iraqi analysts interpreted his remarks as a warning to the United States not to try to pick its own replacement for Maliki, whom many in the West and Iraq hold responsible for the crisis. In eight years in power, he has alienated many in the Sunni minority that dominated the country under ousted dictator Saddam Hussein.
Khamenei has not made clear how far Iran itself will back Maliki to hold on to his job once parliament reconvenes following an election in which Maliki's bloc won the most seats.
Speaking in Cairo, Secretary of State John Kerry said the United States wanted Iraqis to find a leadership that would represent all the country's communities - though he echoed Obama in saying it would not pick or choose those leaders. "The United States would like the Iraqi people to find leadership that is prepared to represent all of the people of Iraq, that is prepared to be inclusive and share power," Kerry said.
The US and Iranian governments had seemed open to collaboration against ISIL, which is also fighting the Iranian-backed president of Syria, whom Washington wants to see removed.
"American authorities are trying to portray this as a sectarian war, but what is happening in Iraq is not