US military helicopters have carried out a raid inside Syria along the Iraqi border, killing eight people including four children, Syrian officials say.
The official Syrian news agency Sana said the attack took place in the Abu Kamal border area, in eastern Syria.
Damascus has condemned the strike as a "serious violation" of its territory.
A US helicopter raid into Syria killed a key figure involved in the smuggling of foreign fighters into Iraq, unnamed US officials have said.
Officials called the raid, which they said killed Iraqi Abu Ghadiyah, a "success". The White House has neither confirmed nor denied the incident.
Syria has condemned Sunday's attack as an act of "terrorist aggression".
It says eight unarmed civilians were killed near Abu Kamal, about eight kilometres (five miles) inside Syria.
If confirmed, this would be the first US attack in Syria since the US-led invasion of Iraq in 2003.