Syria accused the United States on Monday of carrying out a "terrorist aggression" after a raid near its border with Iraq in which eight civilians were killed.
However, the Iraqi government said the attack on Sunday in the Albou Kamal area in eastern Syria targeted "terrorists" who attack Iraq.
Syria's foreign ministry summoned the US charge d'affaires in Damascus on Sunday to protest at the attack.
Foreign Minister Walid al-Moualem later told a news conference in London that Syria would ask the US and Iraq for an investigation into the attack.
He said all those killed were unarmed civilians.
The Arab League denounced the raid and called for an investigation.
US officials say the attack was aimed at the leader of a network that smuggles foreign fighters into Iraq.