February 20, 2007 8:31 AM

PRISTINA, Serbia-A group claimed responsibility Tuesday for a bomb attack that damaged three U.N. vehicles, saying it was in retaliation for the deaths of two ethnic Albanian protesters killed in clashes over a U.N. proposal on the future of the disputed province.

The group, which distributed a statement by e-mail, claimed to be the Kosovo Liberation Army, the now disbanded guerrilla force that fought for independence against Serb forces during the 1998-1999 conflict. It said it had regrouped in order to "avenge the death of two protesters" during a recent demonstration in Pristina.

	U.N. personnel look at the scene where three U.N. vehicles were damaged after an explosion in Kosovo's capital Pristina February 20, 2007.

Police said they were investigating the statement, the authenticity of which could not be independently verified.

Prime Minister Agim Ceku and opposition leader Hashim Thaci, both once leaders of the guerrilla force and now key negotiators on Kosovo's future, did not comment on the statement.

The KLA was disbanded in 1999 under NATO supervision, and part of it was transformed into the Kosovo Protection Corps, a civilian emergency force which condemned Monday's blast. However, a number of illegal groups sprang out in Kosovo after the war, warning U.N. and Kosovo officials against allowing Belgrade to claim authority over the province.

Monday's bombing targeting the U.N. vehicles caused no injuries, but it increased tensions amid ongoing negotiations on the disputed province's future. Ethnic Albanians are impatient to conclude the process they hope will result in Kosovo becoming an independent state, but the Serb minority has warned of secession in the north of the province if that occurs.

Authorities suspect that a bomb had planted under one of the U.N. vehicles, which were all parked in a residential area of Pristina.

U.S. and European Union officials have warned that violence could hamper ethnic Albanians' quest for independence from Serbia.

Ceku, who visited the blast site late Monday, condemned the attack as "an act of those opposing the process of Kosovo's independence."

"Such criminal acts are absolutely unacceptable for Kosovo's people and its institutions," said Kosovo's President Fatmir Sejdiu.

The attack came about 10 days after clashes erupted between police and several thousand ethnic Albanian protesters objecting to a U.N. proposal on Kosovo's final status. They felt the plan, under which Kosovo would be granted internationally supervised statehood, did not go far enough towards giving the province independence.

Two protesters died of rubber bullet wounds to the head, while another 70 were injured in the demonstration.

On Tuesday, activists from the group "Self-determination," which organized the last protest, called for a demonstration against the U.N. plan on March 3.

Kosovo has been a U.N. protectorate since 1999, when NATO bombing halted a Serb military crackdown on ethnic Albanian separatists. The province's ethnic Albanian majority wants full independence, but Belgrade wants Kosovo to remain a part of Serbia.

Ethnic Albanian leaders and Serbian officials are to meet in Vienna, Austria, on Wednesday for a final round of negotiations on the U.N. plan. It will be their last chance to influence the proposal.