Lawmakers in Kosovo argued over a controversial bill. Then came the tear gas.

Opposition lawmakers throw a tear gas canister disrupting a parliamentary session in the Kosovo capital Pristina. Photo / AP

There's civil disobedience.

There's a temper tantrum.

And then there's what this opposition party did to try to delay a controversial vote.

Today, the Kosovo Assembly was voting on whether to accept a new border agreement with Montenegro. The deal - key to gaining Kosovars visa-free travel through the European Union - would cost Kosovo about 78 sq km of land. Kosovo is the only country in the Balkans where citizens still need a visa to travel to the Schengen zone, which includes most EU member states.

The Self-Determination Movement has long opposed the measure, arguing that Kosovo is relinquishing too much territory. The party's leader, Albin Kurti, described the vote as "treason."

It didn't look as if the majority of parliament agreed, though. So to halt the measure, Self-Determination Movement officials set off a couple of tear gas canisters right before voting started, forcing lawmakers to evacuate the chambers. Later, when the Assembly reconvened, the party officials did the same thing. As Reuters reported, the protest caused "deputies to withdraw choking and spluttering."

At least two members were injured, according to AP.

Police arrested a small group of opposition lawmakers. Eight were barred from the session, and seven others were taken to prison.

It took four tries to finally call the session to order. But after voting commenced, the measure passed 80-11. President Hashim Thaci must decree the new border before the deal takes effect, but he has already signalled that he will do so.

Johannes Hahn, the EU commissioner for enlargement negotiations, condemned the fracas in Kosovo's parliament, tweeting that it has "no place in a democracy." The US ambassador to Kosovo was even more blunt, telling reporters, "This should not be happening in a European country. Tear gas is not a European thing."

It's nothing new, at least for the Self-Determination Movement. The party pulled similar stunts in 2015 and 2016.

WOW: Kosovo's opposition party used tear gas to disrupt a parliament vote pic.twitter.com/OrtosZcruO

— Amichai Stein (@AmichaiStein1) March 21, 2018

Kosovo police officers wear gas masks as opposition lawmakers cover their faces after releasing a tear gas canister disrupting a parliamentary session in Kosovo. Photo / AP

Kosovo lawmakers leave as smoke fills the auditorium of the Kosovo assembly. Photo / AP