PRISTINA, Kosovo (AP) — A Kosovo opposition lawmaker and three other supporters have been convicted of terror charges and sentenced to prison over a rocket-propelled grenade attack on parliament.

The Pristina court on Friday sentenced Frasher Krasniqi, lawmaker of the Self-Determination Movement party, to eight years. The three others were imprisoned to between two and six years for the Aug. 4, 2016 attack that damaged the building's exterior but caused no casualties.

The attack occurred amid political tensions over the government's agreement with neighboring Montenegro determining their common border.

Opposition parties vehemently oppose the deal, arguing it cedes territory to Montenegro, which wasn't accepted by the previous government or international experts.

Approval of the deal is a pre-condition for a visa-free regime for Kosovo citizens in the European Union's Schengen countries.