The United States said Thursday it opposed a role by Syria in resolving Iraq's turmoil after President Bashar al-Assad's government was said to have carried out air strikes against militants.
Iraqi Prime Minister Nuri al-Maliki, facing Sunni extremists who have swept across his country from war-torn Syria, told the BBC that Assad's air force this week struck the insurgents on the Syrian side of the border, in a marked escalation.
State Department spokeswoman Marie Harf, while not confirming the air strikes, said that the United States believed military action by Assad would not be "in any way helpful to Iraq's security."
"Iraq's security situation cannot and should not be resolved by the Assad regime, by air strikes from the Assad regime or by militias funded and supported by other countries in the region stepping in," Harf told reporters.
US President Barack Obama, who opposed the 2003 invasion of Iraq, has offered 300 military advisers to help push back the extremist forces but has opposed a wider involvement and blamed Maliki for alienating minorities.
Obama has also resisted calls for intervention in Syria against Assad, who has ruthlessly put down a rebellion waged by both hardline and moderate Sunni rebels.
The chaos comes as the Obama administration explores repairing ties with Iran, a Shiite clerical state that has staunchly supported both Maliki, a fellow Shiite, and Assad, a secular leader from the heterodox Alawite sect.
Harf said that Iran, unlike Syria, "could play a constructive role" in Iraq if it "did things to promote an inclusive government" and did not promote a sectarian Shiite agenda.
Secretary of State John Kerry heads Friday for consultations with US ally Saudi Arabia, a conservative Sunni monarchy which is strongly critical of both Assad and Maliki.