Walid Muallem: We put the responsibility on the American government
Syria's foreign minister has accused the US of an act of "criminal and terrorist aggression" over what it says was a helicopter raid on its territory.
Walid Muallem said Sunday's attack saw four US aircraft travel eight miles inside Syrian airspace from Iraq and kill eight unarmed civilians on a farm.
Unnamed US military officials have said the attack targeted and killed a high profile al-Qaeda operative.
But the White House has not confirmed or denied the alleged raid.
A US official was quoted by the AFP news agency as saying that its forces had mounted a "successful" raid against foreign fighters threatening US forces in Iraq.
He said the raid was believed to have killed "one of the most prominent foreign fighter facilitators in the region".
The BBC's Kim Ghattas in Washington says the person targeted was Abu Ghadiyah, an Iraqi from Mosul.
HAVE YOUR SAY
Whether they could justify a raid or not is irrelevant. They killed eight people in an unannounced attack on an uninvolved country
Michael, Glasgow, Scotland
He was the leader of a network which smuggled fighters into Iraq and had been put on a US Treasury Department black list in February for funding and arming insurgents, says our correspondent.
The military official quoted by AFP said: "Look when you've got an opportunity, an important one, you take it".
"That's what the American people would expect, particularly when it comes to foreign fighters going into Iraq, threatening our forces."
The US has previously accused Syria of allowing militants into Iraq, but Mr Muallem insisted his country was trying to tighten border controls.
Speaking at a news conference in London, Mr Muallem said the raid on the town of Abu Kamal had killed a father and his three children, a farm guard and his wife, and a fisherman.
Mr Muallem said the raid was "not a mistake" and that he had urged the Iraqi government to investigate.
"We consider this criminal and terrorist aggression. We put the responsibility on the American government," he told reporters following talks with UK Foreign Secretary David Miliband.
He added: "All of them [the victims] are civilians, Syrian, unarmed and they are on the Syrian territories.
"Killing civilians in international law means a terrorist aggression."
Asked if Syria would use force if a similar operation was mounted, he said: "As long as you are saying if, I tell you, if they do it again, we will defend our territories."
Referring to the US presidential election, he said: "We hope the coming administration will learn the mistakes of this administration."
Mr Muallem and Mr Miliband were scheduled to hold a joint press conference, but Mr Miliband withdrew. The UK government has declined to comment on the raid.
Exclusive BBC footage of the site of the alleged raid