Controversy flared over the European Union's stance when Straw said - before the talks began - that a path to Kosovan independence was "almost inevitable", signalling the clearest indication so far by a senior Western minister of the likely result of negotiations.
Vuk Draskovic, Serbia-Montenegro's foreign minister, voiced his displeasure on arrival to Austria, telling reporters: "I am surprised because this statement of Mr Straw is against the charter of the United Nations."
Draskovic questioned whether Straw had been speaking for the Contact Group of major powers steering Balkan diplomacy, the EU or the United Nations, adding that Belgrade believed that a compromise was possible, but not on the basis that "might is right".
However, Fatmir Sejdiu, the president of Kosovo, welcomed the comments and thanked Britain, saying Straw's stance was "supportive of the will of the people of Kosovo".
"I am surprised because this statement of Mr Straw is against the charter of the United Nations"
Serbia-Montenegro foreign minister
Javier Solana, the EU foreign policy chief, tried to tone down expectations that the bloc would back a breakaway of the mainly ethnic Albanian Serbian province in UN-mediated talks being conducted by Martti Ahtisaari, the former Finnish president.
"That is a position that is maintained by some countries and it is normal that they stress what for them should be the outcome," he said on his way to the meeting. "But it has not been agreed yet.
"The negotiations have just started under the direction of Mr Ahtisaari. This is something that is beginning to be discussed, but nothing has been decided yet."
Ahtisaari said he did not want to interpret Straw's comments but said: "I think it was a carefully said statement."
Besnik Mustafaj, Albanian foreign minister, said Straw was right, and independence for Kosovo was the only way to create stability in the region.
But some EU colleagues suggested Straw had complicated Ahtisaari's task by coming out so squarely in support of independence and risked slamming doors in Belgrade.
President Tadic says Kosovo
independence is unthinkable
"Mr Ahtisaari has a very very difficult task," Luxembourg's Jean Asselborn said. "We foreign ministers have to have our vision, but we should also be in the corner and let Mr Ahtisaari play. Now we have to be very careful."
Western diplomats have been delivering the message they back a form of independence to Serbs and Kosovo Albanians privately for months, but its precise form is still under discussion.
Some contend that premature public support for independence could ease pressure on the Kosovo Albanians to improve minority rights for the Serbs.
The province of two million people has been run by the United Nations since 1999, when Nato bombing drove out Serbian forces accused of atrocities against ethnic Albanian civilians.
Boris Tadic, the Serbian president, reiterated in an interview with the Austrian daily Die Presse that independence is unthinkable for Belgrade.
"[Kosovo] negotiations have just started under the direction of [mediator] Ahtisaari...nothing has been decided yet"
EU foreign policy chief
"Which political leadership in Europe would allow that part of its territory [to be] cut off," Tadic said. "A solution for Kosovo must not be short-sighted ... You can't try to stabilise Kosovo and at the same time destabilise Serbia."
Serbs are outnumbered 20 to 1 by ethnic Albanians, who have been practically self-governing since 1999. Belgrade wants an autonomous Serb entity with strong ties to Serbia. Albanians say this means partition of Kosovo, a concept ruled out by the West.
The Austrian EU presidency wanted the meeting to refresh the 25-nation group's promise to Albania and the countries that emerged from former Yugoslavia - after three Balkan wars in the 1990s - that their future lies in the European Union.
But the draft final statement has been watered down after countries led by France objected to promising those countries too much in the way of future EU membership.