By Jeremy Bowen
BBC Middle East Editor
Mr Muallem said he did not want relations with Europe to be affected
It was not the visit to London that the Syrian foreign minister Walid Muallem was expecting.
The plan was to meet Britain's foreign secretary, David Miliband, as part of a diplomatic opening to Europe that has already included a visit to Damascus by the French president, Nicholas Sarkozy.
A joint news conference was scheduled at Mr Miliband's official residence, just off the Mall, the processional avenue that leads to Buckingham Palace.
But the attack on Syrian territory changed all of that.
Whether or not Britain was tipped off by the Americans - the British say they were not - the joint appearance was cancelled, hastily.
Mr Muallem appeared alone, just down the street from Mr Miliband's house.
He admitted that no border was 100% secure - after all, he said, the Americans cannot stop Mexicans crossing their border illegally.
But he said Syria was doing all it could to keep its border with Iraq tight - and he condemned what one of the official newspapers in Damascus had already called a war crime.
Killing civilians, he said, was "terrorist aggression".
But Mr Muallem said that he did not want the growing rapprochement between Syria and Europe, especially Britain and France, to be damaged by the attack.
British officials had the same impression during the three hours that Mr Muallem spent with Mr Miliband.
Syria's diplomats have been busy this year.
Syria described the US attack as "terrorist aggression"
There have also been indirect talks with Israel, brokered by Turkey, which Mr Muallem said would stay on hold until the Israelis have a new government.
So the question is why the US has attacked at this precise moment, at the very end of the Bush administration, when security in Iraq is improving and when Syria has been making overtures to the western camp.
The US has been saying for most of the last five years since the invasion of Iraq that Syria should do more to stop jihadist fighters crossing into Iraq.
In Washington, the White House spokeswoman, Dana Perino, would not be drawn.
She told a reporter who pressed her on the matter that "you can come up here and try to beat it out of me, but I will not be commenting on this in any way, shape or form".
But later some reports from Washington were naming a man called Abu Ghadiya as the American target.
The Syrians say that one of the Americans' real intentions was to stop them restoring what they describe as normal ties with Europe.