Armenian Armed Forces are still holding the body of an Azerbaijan serviceman killed in the fighting, said in the statement. The Co-Chairs urge the return, without delay, of human remains, in accord with the agreements of the Astrakhan Summit of 2010, bearing in mind the exclusively humanitarian nature of this issue. "We call upon the Parties to cease mutual accusations and undertake all necessary measures to stabilize the situation on the ground. Violations of the ceasefire are unacceptable"- said in the statement.

A reconnaissance group of the Armenian Armed Forces tried to violate the Azerbaijan-Armenia state border on Dec. 29, 2016. The Armenian group found itself in the ambush of the Azerbaijani army while violating the borders and suffered heavy losses. Chingiz Gurbanov, a serviceman of Azerbaijani Armed Forces, went missing during the fight.

The conflict between the two South Caucasus countries began in 1988 when Armenia made territorial claims against Azerbaijan. As a result of the ensuing war, in 1992 Armenian armed forces occupied 20 percent of Azerbaijan, including the Nagorno-Karabakh region and seven surrounding districts. The 1994 ceasefire agreement was followed by peace negotiations.

Armenia has not yet implemented four UN Security Council resolutions on withdrawal of its armed forces from the Nagorno-Karabakh and the surrounding districts.