The EU and Kosovo have signed an agreement to deepen ties that is seen as a first step towards EU membership.
Prime Minister Isa Mustafa said the agreement "sealed Kosovo's path" towards joining the EU.
Kosovo split from Serbia in 2008, a decade after a conflict between Serb forces and Kosovan Albanian rebels.
Serbia has not recognised Kosovo's independence, but in August it signed key agreements to normalise ties, a condition for its own EU accession.
EU foreign policy chief Federica Mogherini said the deal with Kosovo represented "an important contribution to stability and prosperity in Kosovo and the region at large".
The Stabilisation and Association Agreement is the first key step for non-EU countries on the path towards membership of the bloc.
It requires the country concerned to ensure that its governance and civil society norms - for example on human rights and the judiciary - are brought up to EU standards.
It also involves a commitment to improve trade relations, with candidate countries having to open up their economies in return for EU help.
"It is the road of strengthening democracy and building the rule of law, the road of political stability and economic prosperity," said Mr Mustafa.
In Serbia, the head of the government office for Kosovo Marko Djuric said the agreement "does not and never will mean to us that our province is a separate state".
However, Serbia too is keen to join the EU and Prime Minister Aleksandar Vucic said the country's deal to normalise ties with Kosovo meant there were "no longer any obstacles" in his country's path.
That deal has led to protests by the opposition in Kosovo. MPs have let off tear gas in parliament while demonstrators have clashed with police.
Kosovo, whose population is predominantly ethnic Albanian, fought a war with Serb forces in 1998-1999. The conflict ended after a Nato bombing campaign against Belgrade forced Serbia to back down.