PRISTINA, Kosovo — Kosovo’s opposition has asked the Constitutional Court to annul the recently approved border demarcation deal with Montenegro.

Glauk Konjufca of so-called Self-Determination! took the claim to the court on Thursday, arguing that “lawmakers violated the Constitution with an anti-constitutional decision.”

Earlier this month, the border deal won parliamentary approval despite the opposition’s use of tear gas in the chamber to prevent a vote.

The European Union says a border agreement is a precondition for Kosovo’s citizens to travel without visas into Europe’s Schengen travel zone.

The opposition says Kosovo loses territory, a claim denied by the government and international experts.

Montenegro, which has approved the deal, recognizes Kosovo’s 2008 independence from Serbia, which Belgrade still rejects.