YEREVAN, Armenia (AP) — Three men were charged with terror offences Sunday after attempting to storm a police station in the Armenian capital of Yerevan, detonating hand grenades that injured two of the attackers, an internal affairs ministry official said.

A third man stood in the entrance to the station for more than an hour threatening to set off another grenade. Police units headed by Armenia’s deputy internal affairs minister, Aram Hovhannisyan, rushed to the scene and were ultimately able to detain the attacker. The assailant was being held in the Nor-Nork police station, said Narek Sargsyan, spokesperson for Armenia’s Ministry of Internal Affairs. There were no other reported injuries.

Sargsyan did not confirm any of the demands made by the third attacker. Armenian media outlets reported Sunday that the men had hoped to free members of the Combat Brotherhood organization, who were being held at the station after being detained earlier that day.

The group opposes the planned transfer of several villages in Armenia’s Tavush region to neighboring Azerbaijan.

Last year, Azerbaijan waged a lightning military campaign to reclaim the Karabakh region, ending three decades of ethnic Armenian separatist rule there.

In December, the two sides agreed to begin negotiations on a peace treaty. However, many residents of Armenia’s border regions have resisted the demarcation effort, seeing it as Azerbaijan’s encroachment on the areas they consider their own.

Speaking to residents of the border village of Voskepar in the Tavush region Tuesday, Prime Minister Nikol Pashinyan warned that Armenia’s refusal to delineate the border could trigger a new confrontation.

“It would mean that a war could erupt by the end of the week,” Pashinyan said. He said the border demarcation should be based on mutual recognition of territorial integrity of Armenia and Azerbaijan based on Soviet maps from 1991, when both were part of the Soviet Union.