Kosovo unilaterally self proclaimed independence from Serbia in 2008, a move which Serbia strongly rejects. Serbia does not recognize Kosovo as an independent state and continues to claim it as the Autonomous Province of Kosovo and Metohija. However, differences and disputes remain, while North Kosovo is partially under Serbian rule. Initially there were no relations between the two; but in the following years there has been increased dialogue and cooperation between the two sides.
Kosovo isn’t a member, nor observer state of United Nations, or any other international organisations, it remains a partially recognised country. According to the international law, and Resolution 1244, which ended the Kosovo war it is claimed by Serbia as the Autonomous Province of Kosovo and Metohija.
However, a series of events in 2022-2023 -- including election disputes in Kosovo, a Serb "terrorist" attack on Kosovo, and Serb troops massing on the border -- led to rising tensions between the countries. Kosovo authorities accused Russia of aggravating the situation, in part to compensate for its own failings in its simultaneous invasion of Ukraine.
Negotiations facilitated by the European Union resulted in the 2013 Brussels Agreement on the normalization of relations between the governments of Kosovo and Serbia. The agreement pledged both sides not to block the other in the EU accession process, defined the structure of the police and local elections in all parts of Kosovo, and also established the proposal of the Community of Serb Municipalities.
The United States-mediated diplomatic talks agreed on the interconnection of air, train and road traffic, while both parties signed the 2020 agreement on the normalisation of economic relations. Kosovo and Serbia are expected to become part of the single market, known as Open Balkan.
Both parties agreed to a proposed normalisation agreement in EU mediated dialogue in February 2023 and through further negotiations accepted a roadmap and timescale for its implementation the following month.
Reaction to declaration of independence
Serbia strongly opposed Kosovo's declaration of independence, which was declared on 17 February 2008. On 12 February 2008, the Government of Serbia instituted an Action Plan to combat Kosovo's anticipated declaration, which stipulated, among other things, recalling the Serbian ambassadors for consultations in protest from any state recognising Kosovo, which it has consistently done. Activities of ambassadors from countries that have recognised independence are limited to meetings with Foreign Ministry lower officials. The Serbian Ministry of the Interior issued an arrest warrant against Hashim Thaçi, Fatmir Sejdiu and Jakup Krasniqi on 18 February 2008 on charges of high treason.
On 8 March 2008, the Serbian Prime Minister Vojislav Koštunica resigned, dissolving the coalition government, saying it was too divided over the Kosovo situation to carry on. A pre-term parliamentary election was held on 11 May 2008, together with local elections. President Boris Tadić stated that the government fell "because there was no agreement regarding further EU integration".
On 24 March 2008, Slobodan Samardžić, Minister for Kosovo and Metohija, proposed partitioning Kosovo along ethnic lines, asking the United Nations to ensure that Belgrade can control key institutions and functions in areas where Serbs form a majority but other members of the Government and the President denied these claims. On 25 March 2008, the outgoing Prime Minister, Vojislav Koštunica stated that membership in the EU should be "left aside", until Brussels stated whether it recognised Serbia within its existing borders.
On 24 July 2008, the Government decided to return its ambassadors to EU countries. Other ambassadors were returned following the positive outcome of the vote in the UN General Assembly. Serbia has expelled diplomatic representations of all neighboring countries that subsequently recognised Kosovo's independence: Albania, Bulgaria, Croatia, Hungary, Montenegro, and North Macedonia.
On 15 August 2008, Serbian Foreign Minister Vuk Jeremić filed a request at the United Nations seeking a non-legally binding advisory opinion of the International Court of Justice of whether the declaration of independence was in breach of international law. The United Nations General Assembly adopted this proposal on 8 October 2008. In July 2010, the ICJ issued its opinion which found that Kosovo's declaration of independence "did not violate international law".