Serbia's parliament on Friday began debating whether to green light an EU-brokered deal aimed at normalizing ties with former foe Kosovo, a landmark accord already approved by the government.

The deal, which has come under fire from ultra-nationalists and Kosovo Serbs, is expected to win vast backing in the 250-seat parliament, as MPs from the ruling nationalists' coalition and from the center-left opposition have already indicated they would vote in favor of it.

Serbia's nationalist President Tomislav Nikolic on Thursday personally apologised for the first time for the 1995 Srebrenica massacre of 8,000 Muslims, but stopped short of calling it genocide.

"I kneel and ask for forgiveness for Serbia for the crime committed in Srebrenica," Nikolic said of the slaughter, the worst atrocity in Europe since World War II.

Serbia's government on Monday approved an EU-brokered deal to normalize ties with breakaway Kosovo, a historic agreement aimed at turning the page on the Balkans' last simmering trouble-spot 14 years after the end of hostilities.

The premiers of Serbia and Kosovo on Friday initialed a historic deal to normalize ties in a move key to the future of the Western Balkans, said EU foreign policy chief Catherine Ashton.

"These negotiations have been concluded," Ashton said. "The text has been initialed by both prime ministers."

Serbia and Kosovo again failed to clinch a deal to normalize ties and ease tension in the Balkans after lengthy talks brokered by the European Union lasting through Wednesday until Thursday.

"Today has been a very long and intensive day," said EU foreign policy chief Catherine Ashton at the close of negotiations that began early Wednesday but ended after midnight.

The United States on Wednesday led a boycott of a U.N. meeting where Serbia's President Tomislav Nikolic launched a fierce attack on international war crimes tribunals.

The U.S. mission condemned the meeting organized by the head of the U.N. General Assembly, Serbia's Vuk Jeremic, as "unbalanced" and "inflammatory."

Russia on Wednesday vowed to extend economically struggling Serbia a $500-million loan while reasserting support for its ally's continuing refusal to recognize the independence of Kosovo.

Serbian Prime Minister Ivica Dacic won a promise of the quick disbursement of a $300-million (230-million-euro) loan that would help cover Belgrade's budget shortfall.

Wartime Bosnian Serb army chief Ratko Mladic was removed from a U.N. war crimes court Wednesday for challenging harrowing testimony from a survivor of the 1995 Srebrenica massacre.

Mladic, who is on trial at the court in The Hague on various charges, including genocide, over the 1992-95 Bosnian war, began muttering as the witness started testifying about Srebrenica, the worst atrocity in Europe since World War II.

Serbia rejected on Monday a Brussels-brokered proposal on easing tensions with breakaway Kosovo, seen as a key condition for EU integration talks to begin, but pledged to continue negotiations with Pristina.

"The government of Serbia cannot accept principles verbally presented to its negotiating team in Brussels, since they do not guarantee full security and protection of human rights to the Serb people in Kosovo," Serbian Prime Minister Ivica Dacic told reporters.

Serbia should refuse to sign an EU-brokered proposal on easing tensions with Kosovo, but continue talks with Pristina, Deputy Prime Minister Aleksandar Vucic said Monday.

"Our suggestion to the government of Serbia is that... we do not sign what does not take into consideration even the minimum of our national interests," Vucic told reporters after a meeting of his SNS party leadership.