Kosovo’s parliament approved an EU-backed border demarcation deal on Wednesday despite opposition MPs releasing tear gas in the chamber to try to thwart the vote.

The EU made ratifying the deal with Montenegro a condition that Kosovo must fulfil before its citizens are granted visa-free travel to the bloc’s Schengen zone.

Eighty MPs in the 120-seat parliament voted in favour of the deal — just enough to seal ratification, regional news outlet Balkan Insight reported.

Opposition politicians have alleged that the agreement gives away 8,000 hectares of Kosovo’s territory to Montenegro.

Earlier in the day, MPs from the opposition Movement for Self-Determination threw tear gas cannisters as parliamentary speaker Kadri Veseli was asking MPs to vote on the deal. All MPs had to leave the room.

The Movement for Self-Determination has a history of using tear gas to try to disrupt parliamentary proceedings.

European Commissioner Johannes Hahn, who is responsible for relations with the bloc’s neighbors, condemned the opposition MPs’ actions on Twitter.

“Such behaviour has no place in a democracy. On this important day, #Kosovo leaders must assume their #responsibilities and vote the #demarcation agreement. Their citizens can only benefit from this step,” he said.

Greg Delawie, the U.S. ambassador to Kosovo, expressed the same view. “Violence as a political tool has no place in #Kosovo,” he tweeted.

This article has been updated.