Ambassadors Igor Popov of Russia, Stephane Visconti of France, and Richard Hoagland of the United States cited "information collected from multiple reliable sources" which proved that Azerbaijan initiated the latest escalation on the contact line.

"According to information collected from multiple reliable sources, on 15 May, Azerbaijani armed forces fired a missile across the line of contact, striking military equipment. On the evening of 16 May and continuing into 17 May, Armenian armed forces retaliated with mortar fire of various calibres. These actions by both sides represent significant violations of the ceasefire and are cause for alarm," the statement said.

"There are contradictory reports regarding the targets of these recent strikes, as well as about casualties sustained and damages inflicted. The Minsk Group co-chairs and the Personal Representative of the OSCE Chairperson-in-Office continue to collect further data and analysis to gain more complete and accurate information about the current situation."

Also, the co-chairs called upon the sides to take all necessary measures to prevent any further escalation in the conflict zone.

Video footage unveiled on May 17 revealed Azerbaijan's sheling of an Artsakh military objective several days ago and Karabakh's retaliatory fire.