The United States has carried out a helicopter raid inside Syria, killing eight people including four children, according to Syrian officials.
The official Syrian news agency Sana said four helicopters were used during the attack in the Abu Kamal border area.
Syria has summoned the US and Iraqi charge d'affaires to Damascus to protest against the raid, the Syrian Arab news agency (Sana) reported last night.
It is reported that American soldiers landed in helicopters in the village of Sukkiraya, 8km (5 miles) from the Iraqi border on Sunday night. The troops then stormed a building under construction.
"Four American helicopters violated Syrian airspace around 1645 local time [1345 GMT] on Sunday.
"American soldiers emerged from helicopters and attacked a civilian building under construction and opened fire on the workers that were inside leading to the deaths of eight civilians.
"The helicopters then left Syrian territory towards Iraqi territory," Sana said.
A resident speaking on condition of anonymity said the helicopters flew along the Euphrates River into the area of farms and factories. He said that some of the helicopters landed, commandos exited the aircraft, then fired on a building.
Sana said that the civilian victims have now been identified as Daoud Mohammad al-Abdullah, his four sons, Ahmad Khalefa, Ali Abbas and his wife in addition to wounding another Syrian citizen.
"Syria condemns and denounces this act of aggression and US forces will bear the responsibility for any consequences," a Syrian government official said.
"Syria also demands that the Iraqi government accept its responsibilities and launches an immediate inquiry following this dangerous violation and forbids the use of Iraqi territory to launch attacks on Syria," the official added.
The United States said it was investigating the reports.
The US has previously accused Syria of allowing foreign militants into Iraq. However last month Jalal Talabani, Iraq's president, told his US counterpart George Bush that Syria and Iran no longer pose a problem to Iraq's security.
Syrian officials called the incident a "war crime." A Syrian diplomat in London told the BBC that Syria reserves the right to retaliate.