Kosovo's government proposed on Thursday creating a 5,000-strong army to "protect sovereignty" of the ethnic Albanian territory, six years after it seceded from Serbia.

The army would double the size of the current civil emergency Kosovo security force (KPS), said a statement issued after a cabinet session.

Since the end of 1998-1999 war between independent-seeking ethnic Albanian guerrillas and Belgrade forces under the command of late strongman Slobodan Milosevic, NATO has been in charge of maintaining peace and security in Kosovo.

The lightly-armed KPS, created with NATO assistance in 2009, is tasked with dealing with emergency response and protection of public and civil order.

However, this proposal, which would require a change to Kosovo's constitution, would push the KPS into new areas of operation.

Prime Minister Hashim Thaci said the "armed forces of Kosovo will protect the sovereignty, territorial integrity, citizens, property and interests" of Kosovo, a statement said.

The future army will also have 3,000 reservists, with a yearly budget of 65 million euros ($89.5 million).

The forces are expected to be fully operational after 2019, it added.

In Belgrade, Serbia's Minister in charge of Kosovo Aleksandar Vulin said his government would demand an emergency UN security Council session to discuss Pristina's move.

"This is unacceptable and fully against UN resolution 1244 which clearly states that there can be no army on Kosovo's territory," Vulin told reporters.

That resolution, adopted in 1999, put Kosovo under UN administration and set up NATO-led peacekeepers (KFOR) to maintain peace in the former Serbian province.

Since Pristina declared independence from Serbia in February 2008, Kosovo has been recognised by more than 100 countries, including the United States and all but five European Union members.

Although Serbia still does not recognise its independence, Belgrade and Pristina have reached an accord on improving relations under the EU mediation last April.

But Serbian Prime Minister Ivica Dacic said a possible creation of Kosovo army was "not in accordance" with the agreement.