Bulgaria, Croatia and Hungary have recognized Kosova's declaration of independence, the latest blow to neighboring Serbia's attempts to resist the province's breakaway.
Serbia warned the three nations that their relations with Belgrade would suffer following their joint statement on Wednesday.
"The decision on the recognition of Kosova is based on thorough consideration," Bulgaria, Croatia and Hungary said in their statement.
Thirty-two countries have now given diplomatic support to Kosova, which unilaterally declared independence on February 17.
The move came after two days of violence by ethnic Serbs, protesting against the declaration of independence, in the ethnic divided northern city of Mitrovica.
UN police redeployed
On Wednesday, UN police were redeployed in the north of the city. They had withdrawn after a Ukrainian officer was killed and more than 150 people injured in Monday's rioting.
Nato-led Kosova Force peacekeepers had been patrolling the streets in the UN's absence.
David McLean, the regional police commander in Mitrovica, said the UN police were returning "gradually" and setting up their operation and patrols.
He said he expected to restore the mission "as quickly as possible".
Alexander Ivanko, spokesman for the UN mission that has administered Kosova since Nato bombing drove out Serbian forces in 1999, blamed Serbian officials for the violence that followed the seizure of UN court buildings by demonstrators.
"I can tell you that we have rock solid proof that there were officials of the [Serbian] ministry of interior present at the court house," he said.
'Illegal state'
Vuk Jeremic, Serbia's foreign minister, reacted coldly the decision by Hungary, Croatia and Bulgaria to recognize Kosova.
"Every country that makes this move cannot count on good relations with us," he said during a trip to Athens. "Every country that recognizes the illegal state of Kosova violates international law."
Croatia's recognition, the second by a former Yugoslav republic after Slovenia, is expected to be the most sensitive, as it threatens to harm delicate post-war ties between the two neighbors.
Ahead of the announcement, Boris Tadic, Serbia's president, warned Croatia against the move, saying it would have an "immediate impact on our bilateral ties".
Slobodan Uzelac, Croatia's deputy prime minister who represents the country's Serb minority, handed in his resignation in protest at Zagreb's decision, according to Ivo Sanader, the prime minister.
Belgrade has so far recalled ambassadors from 29 countries that have accepted Kosova's independence, but is yet to announce its response to the latest recognitions.
PHOTO CAPTION
Nato-led soldiers in Kosova
Al-Jazeera