By Jonathan Marcus
Diplomatic correspondent, BBC News
Syria has said American troops carried out a raid inside Syria along the Iraqi border, killing eight people - if the claims are true then this will be the first military incursion by the US into Syrian territory from Iraq.
Syria's foreign minister Walid al-Muallem met US officials at the UN
But its timing is curious, coming right at the end of the Bush administration's period of office and at a moment when many of America's European allies - like Britain and France - are trying to broaden their ties with Damascus.
Whatever the local military factors involved in this US operation, it would be unthinkable to imagine that an incursion into Syria would not require a policy decision at a high-level.
The movement of insurgents and foreign fighters from Syria into Iraq has long been a bone of contention between Damascus and Washington.
The US argument has always been that the Syrians are not doing enough to control the border. The Syrians have always countered that they are unfairly being blamed for turmoil inside Iraq that is not of their making.
Quite apart from their differences over Iraq, Washington sees Syria as unhelpful in Lebanon and as far too friendly with Iran.
While there have been relatively high-level contacts between the two governments - US Secretary of State Condoleezza Rice meeting the Syrian Foreign Minister Walid al-Muallem on the sidelines of the UN General Assembly just a few weeks ago - they have hardly generated any warmth.
Washington has even been lukewarm to Turkey's efforts to broker a peace deal between Israel and Syria.
Nicolas Sarkozy (r) has sought to warm relations with his Syrian counterpart
All of this is in marked contrast to European efforts to engage the Syrians.
With French President Nicolas Sarkozy in the lead, a number of European countries have sought to bring Syria in from the cold.
But despite glimmerings of dissent from the State Department, the Bush administration has held firm to its policy of no substantive talks with Syria unless - as the Americans put it - Damascus decides to take a more "positive role" in the region.
With the Bush administration on the way out, this US military incursion may represent something of a parting shot against the Syrians.
It's clear that if Senator Barrack Obama were to win the White House, his key advisers are among the strongest advocates of engaging with Damascus across a broad spectrum of issues.