Tear gas has been released in Kosovo's parliament by opposition MPs in a bid to stop a vote on a border demarcation agreement with Montenegro.

The Self-Determination Movement party used three tear gas canisters in the Assembly building as the vote was due to start on Wednesday, forcing all politicians to leave the hall.

The 120-seat parliament was expected to vote with the two-thirds needed to ratify the 2015 agreement.

The Movement party claims the deal would see Kosovo lose 20,000 acres of its territory to its neighbour, though experts dispute this.

US ambassador to Kosovo, Greg Delawie, condemned the "violence" as a "political tool" with "no place" in the country.

"I urge MPs to reconvene and finish the vote today," he added.

Nataliya Apostolova, the European Union's ambassador, said on Twitter: "Appalled by tear gas release in Kosovo Assembly! Shocked that members of a parliament in Europe are resorting to dangerous tactics pulling Kosovo backwards.

"[I] call on all MPs and all parties to go back to [the] Assembly to defeat such unacceptable practices that go against democratic society and the future of the Kosovo people. MPs, vote for the future, not for the past!"

Opposition members release tear gas inside Kosovo parliament Show all 10 1 /10 Opposition members release tear gas inside Kosovo parliament Opposition members release tear gas inside Kosovo parliament Kosovo's opposition lawmakers release a teargas canister inside the country's parliament in Pristina. AFP/Getty Opposition members release tear gas inside Kosovo parliament Kosovo's opposition lawmakers release a teargas canister. AFP/Getty Opposition members release tear gas inside Kosovo parliament People in parliament react as the canister hits the floor. AFP/Getty Opposition members release tear gas inside Kosovo parliament Attempts to remove the canister away from other members in the parliament. AFP/Getty Images Opposition members release tear gas inside Kosovo parliament Ratification of the border agreement between Kosovo and Montenegro is set by European Union as the main condition before it will grant Kosovo nationals visa-free access to the Schengen area. AP Opposition members release tear gas inside Kosovo parliament A closer shot of Kosovo's opposition lawmakers releasing a teargas canister inside the country's parliament in Pristina. AFP/Getty Opposition members release tear gas inside Kosovo parliament Two men further attempt to dispose of the canister. EPA Opposition members release tear gas inside Kosovo parliament Tear gas rises from a canister released by Kosovo opposition lawmakers. EPA Opposition members release tear gas inside Kosovo parliament A lawmaker of the ruling coalition removes the tear gas canister. EPA Opposition members release tear gas inside Kosovo parliament Kosovo lawmakers leave as smoke fills the auditorium of the Kosovo assembly. AP

The proposed land deal is a precondition set by the EU in order to give Kosovans the ability to travel freely inside the visa-free Schengen area. Montenegro has already approved the deal.

Kosovo declared independence from Serbia in 2008 - though this is not recognised by Belgrade - and hopes to qualify for EU membership in the future.