Saudi Arabia became the second key American ally in the Middle East to demand President Barack Obama change tack towards Iran on Thursday, as it called for US-led coalition "boots on the ground" to fight Isil.
Prince Saud al-Faisal, the Saudi foreign minister, told John Kerry, the US secretary of state, that he risked allowing Iran to "take over Iraq", echoing Israel's recent concerns over the White House's policy toward Tehran.
The United States and its coalition allies are attacking Islamic State of Iraq and the Levant (Isil) positions from the air in both Syria and Iraq, but refusing to send troops. As a result, outside Kurdish areas the offensive in both countries is heavily influenced by Iran and its proxy Shia militias such as Hizbollah.
This has raised serious concerns in Saudi Arabia, Iran's Sunni rival for Middle East dominance.
The Iraqi government is currently attacking Isil positions in Tikrit, Saddam Hussein's hometown north of Baghdad. But most of its forces are under the command of government-aligned Shia militias, whose leaders are close to the Iranian regime, even though the population of Tikrit is largely Sunni.