Six Armenian soldiers were killed in border clashes in the last two days, according to the Azerbaijani Ministry of Defense.
In a statement, the ministry said the Armenian soldiers were killed as part of a retaliatory measure against artillery fire from the Armenian side.
It said one Azerbaijani soldier was also killed in the clash.
The two countries dispute the occupied Karabakh region, which pro-Armenian militia took over in 1993, and clashes are nothing new.
In April 2016, more than 270 military personnel lost their lives in the worst-ever breach of a 1994 treaty between both sides, according to the Azerbaijani Defense Ministry.
Three UN Security Council Resolutions (853, 874 and 884), and United Nations General Assembly Resolutions 19/13 and 57/298 refer to Karabakh as part of Azerbaijan.
The Parliamentary Assembly of the Council of Europe refers to the region as being occupied by Armenian forces.