(Reuters) - The European Union said that renewed escalation of the conflict in eastern Ukraine violated the spirit and the letter of a ceasefire.
"The Minsk Agreements must be implemented in good faith, starting with full observation of the ceasefire and genuine withdrawal of heavy weapons", the EU's External Action Service said in a statement on Tuesday.
Ukraine on Monday accused rebels of carrying out the heaviest artillery attacks since the truce was agreed. Russia blamed Kiev.
The Minsk deal, signed in February, calls for a ceasefire between Ukrainian forces and Russian-backed separatists, the withdrawal of heavy weapons from the front line and constitutional reform to give eastern Ukraine more autonomy.