Serbia's parliament on Friday began debating whether to green light an EU-brokered deal aimed at normalising 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 centre-left opposition have already indicated they would vote in favour of it.
The premiers of Serbia and Kosovo hammered out the deal on April 19 with both sides under strong pressure from Brussels to improve relations if they want to move closer to the European Union.
The agreement was signed by the Serbian government on Monday but needs to be approved by parliament as well.
The accord gives some autonomy to Kosovo Serbs living in northern Kosovo, who refuse to recognise Pristina's authority. While it has won praise from EU officials, it has angered many Serbs who see it as tacit acceptance by Belgrade of the breakaway territory's independence.
There was a heavy police presence outside the parliament building on Friday where several hundred ultra-nationalist supporters gathered to protest against the accord.
The demonstrators shouted "treason!" and "you betrayed Kosovo" at deputies heading into the session, and carried placards labelling the prime minister and the president "traitors".
Only the ultra-nationalist and Euro-sceptic Democratic Party of Serbia (DSS), which holds 21 seats in parliament, openly opposes the deal.
Addressing parliament, Serbian Prime Minister Ivica Dacic said Serbia "has not had (control in) Kosovo for a long time".
"Somebody had to do this (reach an agreement with Kosovo)... in order to put an end to the past," he said.
"This was to be or not to be, not only for the north of Kosovo, but for the whole of Serbia," Dacic said, drawing boos from DSS deputies.
The government has indicated it might organise a referendum on the agreement in order to silence the opponents and ensure easier implementation in the field in northern Kosovo.
EU Enlargement Commissioner Stefan Fuele, who was visiting Belgrade Friday, said it was up to Serbian authorities to chose the way "to ensure that all the stakeholders are on the board when it comes to implementation."
"Whatever the way they chose it should not delay the process but in the end make sure that the implementation is sustainable," Fuele told reporters after meeting President Tomislav Nikolic.
An agreement on improved ties with Kosovo, aimed at turning the page on the last simmering troublespot in the Balkans, was the last major hurdle in Belgrade's efforts to be given a date to kick off long-awaited EU accession talks.
In response, the European Commission on Monday recommended the launch of formal negotiations on Serbia's EU entry. It also recommended starting negotiations with Kosovo on an agreement that would bring Pristina closer to the 27-nation bloc.
Belgrade and Kosovo Serbs refuse to recognise the 2008 independence of Kosovo, although more than 90 countries, including the United States and all but five EU member states, have done so.
Serbia lost control over its former southern province in June 1999 after a NATO bombing campaign halted late strongman Slobodan Milosevic's crackdown against the pro-independence ethnic Albanian majority and ousted Serbian armed forced from Kosovo.