Mounting attacks in government-held areas of eastern Ukraine violate a February peace deal with pro-Russian separatists, the EU says.
"The renewed escalation of the conflict... as a result of attacks on several government-controlled areas today ... violates the spirit and the letter of the Minsk Agreements," the EU's External Action Service said in a statement on Tuesday (local time), referring to the accord signed in the capital of Belarus.
The EU's diplomatic arm condemned an arson attack on Sunday on armoured vehicles belonging to OSCE truce monitors as well as the fact that the monitors have been caught in the crossfire in Shchastya and Shyrokyne.
These incidents "put in danger the crucial role that the SMM (Special Monitoring Mission of the OSCE) plays in monitoring and verifying the implementation of the Minsk agreements," it said.
The EU did not explicitly blame the rebels in the statement, underlining that the peace agreement "is the basis for a sustainable solution of the conflict in full respect of Ukraine's independence, sovereignty and territorial integrity."
The number of attacks on OSCE observers has increased in recent weeks in eastern Ukraine, where the conflict between government troops and pro-Russian separatists has claimed more than 6800 lives in 15 months.
The EU renewed its call for full respect of the ceasefire and a genuine withdrawal of heavy weapons under the terms of the peace agreement.