The Armenian military pledged to retaliate strongly after three Armenian civilians were killed and two others wounded on Thursday when their border villages came under fire from nearby Azerbaijani army positions.

Their deaths marked a fresh escalation of tensions at the westernmost section of Armenia’s border with Azerbaijan ahead of a meeting in New York between the foreign ministers of the two warring nations.

Two of the Armenian civilians, the 41-year-old Sona Revazian and 94-year-old Shushan Asatrian, were killed in Bertavan, a village in the northern Tavush province bordering the Gazakh district in western Azerbaijan. According to the local police, two other Bertavan residents were wounded by Azerbaijani gunfire.

The third victim, also a woman, lived in another Tavush village, Paravakar. Paytsar Aghajanian was 83.

The Armenian Defense Ministry accused the Azerbaijani side of violating the ceasefire regime in that area with mortars and automatic weapons and vowed to strike back hard. “We are calling on the Azerbaijani civilians living along the border with Armenia to stop serving as a human shield for their armed forces,” the ministry said in a statement.

“In order to stabilize the situation in the border area and rein in Azerbaijani forces, the Armenian Armed Forces will resort to adequate actions,” it said. “Azerbaijan’s military and political leadership will bear full responsibility for the consequences of that.”

The Azerbaijani side did not immediately comment on the Armenian civilian deaths and the tough retaliation promised by Yerevan.

News reports from Baku earlier in the day said that a female resident of an Azerbaijani border village in Gazakh was wounded on Wednesday in an Armenian truce violation and hospitalized as a result. The Azerbaijani Defense Ministry said its troops responded with “powerful strikes” on Armenian territory.

Tension at that border section already intensified dramatically less than a month ago. Villages on both sides of the frontier were directly hit in mostly overnight skirmishes between Armenian and Azerbaijani troops stationed in the area. Several civilians were wounded as a result.

The United States expressed serious concern at that escalation, saying that both conflicting parties shelled each other’s border villages. “We call for an immediate end to such violence,” a State Department spokesman said on September 10.

The latest upsurge in fighting comes ahead of talks which the Armenian and Azerbaijani foreign ministers are due to hold on the sidelines of a UN General Assembly session in New York. The U.S., Russian and French mediators trying to broker a solution to the Nagorno-Karabakh conflict hope that the talks will pave the way for a fresh meeting of the Armenian and Azerbaijani presidents later this year.

James Warlick, the U.S. mediator, tweeted later on Thursday that he and his Russian and French colleagues are “in touch with officials in Armenia and Azerbaijan about the renewed violence” and are “urging an end to attacks and reprisals.”