Meeting with Armenia's president in Brussels, the head of the European Council on Wednesday called for an end to the fighting in Nagorno-Karabakh or Upper Karabakh, Azerbaijani territory occupied by Armenia.
Speaking with Armenia's Armen Sarkissian, Charles Michel repeated the EU's "deepest concern" about ongoing fighting with major humanitarian costs.
"Parties must respect ceasefire and return to negotiating table without preconditions. External interference is unacceptable," he said on Twitter, after the meeting.
Turkey and Azerbaijan have both decried Armenian violations of the current temporary humanitarian cease-fire.
Sarkissian is also set to meet NATO Secretary General Jens Stoltenberg in Brussels later today.
Since fresh clashes erupted on Sept. 27, Armenia has continued its attacks on civilians and Azerbaijani forces, even violating humanitarian cease-fire agreements.
In two missile attacks on Ganja, a major Azerbaijani city far from the front line, Armenia killed some two dozen civilians, including children, and injured scores more.
Last Thursday, Armenia targeted civilians at a cemetery in the western city of Tartar, killing four and injuring four others.
Over the past 10 days, Armenia has violated two humanitarian cease-fires in Upper Karabakh, or Nagorno-Karabakh, an internationally recognized territory of Azerbaijan.
A new humanitarian cease-fire entered into force last Saturday.
Relations between the two former Soviet republics have been tense since 1991, when the Armenian military occupied Upper Karabakh.
Four UN Security Council resolutions and two from the UN General Assembly, as well as international organizations, demand the "immediate complete and unconditional withdrawal of the occupying forces" from occupied Azerbaijani territory.
In total, about 20% of Azerbaijan's territory-including Nagorno-Karabakh and seven adjacent regions-has been under illegal Armenian occupation for nearly three decades.
The Organization for Security and Co-operation in Europe (OSCE) Minsk Group-co-chaired by France, Russia, and the US-was formed in 1992 to find a peaceful solution to the conflict, but to no avail. A cease-fire, however, was agreed to in 1994.
World powers, including Russia, France, and the US, have called for a sustainable cease-fire. Turkey, meanwhile, has supported Baku's right to self-defense and demanded the withdrawal of Armenia's occupying forces.
