Kosovo’s parliament has approved a plan to turn its security force into a full army over the objections of NATO, which maintains a force in the country.

The legislation passed with a unanimous yes vote in a Friday, December 14 session boycotted by minority Serb MPs, an AFP reporter said.

The assembly still needs to adopt one final piece of legislation that lays out the new organizational structure of the Kosovo Security Force, an emergency response outfit that will be tranformed into “an organization with the mandate of defense of the country,” according to the new law.

Since the end of the 1998-99 war that effectively cleaved it from Serbia, Kosovo has been defended by international NATO-led troops.

Last week the U.S. ambassador to Pristina said the United States supports Kosovo’s plan, signaling a rift with NATO, which is against the move.

NATO Secretary-General Jens Stoltenberg said on December 5 that Kosovo’s army plans are “ill-timed” and go “against the advice of many NATO allies.”

On Friday, Stoltenberg said he regretted the move “despite the concerns expressed by NATO.”

“With the change of mandate, the North Atlantic Council will now have to re-examine the level of NATO’s engagement with the Kosovo Security Force,” he said in a statement.

“All sides must ensure that today’s decision will not further increase tensions in the region. All responsible political actors in the region need to focus on progress with reforms, and on dialogue.”

The process of forming a national army could take Kosovo up to 10 years, according to officials.

Serbian Prime Minister Ana Brnabic said Friday that her country would “stay on its path of peace and prosperity.”

“For me this is a hard day, not a day that contributes to cooperation in the region,” she told local reporters.

Serbia has led the charge in raising concern over Kosovo’s army plans. It refuses to recognize Kosovo’s independence and still considers it a renegade territory.

More than 13,000 people, mostly ethnic Albanians, were killed in the 1998-1999 war between ethnic Albanian guerillas in Kosovo and Serbian forces.

The conflict ended when a NATO bombing forced Serbian troops to withdraw.

With reporting from AFP