Syria has accused US troops of killing at least eight civilians, including four children, in a helicopter raid inside Syrian territory close to the border with Iraq.

A Syrian government statement said four helicopters were involved in the attack on a building near the town of Abu Kamal, five miles inside the Syrian border.

Syrian Foreign Minister Walid al-Moualem accused the US of carrying out a ‘terrorist aggression’ on the country.

‘The Americans do it in the daylight, this means it is not a mistake, its by blunt determination.

‘For that we consider this criminal and terrorist aggression,’ Mr Moualem told a news conference in London.

President Muallem said all of the victims were unarmed civilians and that Damascus would defend its territories if the US repeated any such action.

He added that Syria would ask the US and Iraq for an investigation into the attack.

Earlier, a US official in Washington said US forces crossed into Syria in a raid against foreign fighters.