The mission monitoring the cease-fire in Ukraine is warning that violations are becoming more frequent and severe, with heavy weapons often missing from storage areas and rockets and multiple rocket launchers recently being used again.

Alexander Hug, the deputy chief monitor of the Organization for Security and Cooperation in Europe's mission in Ukraine, told the U.N. Security Council by videoconference Friday that monitors have noted the movement and presence of heavy weapons — "not to mention the obvious use of such weapons" — in areas prohibited by February's cease-fire agreement.

He said these developments, and especially Wednesday's upsurge in fighting in the Donetsk suburb of Marinka, "serve as a stark reminder for all sides of the need to resolve their differences at the negotiating table."