At least nine people have died in heavy exchanges of artillery fire between Ukrainian government forces and pro-Russian rebels in eastern Ukraine.
Seven were civilians and two were government soldiers, reports said.
Russia’s Foreign Minister Sergei Lavrov said the latest fighting suggested preparations for a new offensives by the Kiev government’s forces.
Kiev accused the rebels of shelling the outskirts of Mariupol, a key port city from 12km (7.4 miles) away.
The latest escalation has left the ceasefire signed in February looking more fragile than ever.
Kiev, Western governments and Nato say there is clear evidence of Russian regular troops helping the separatists and arming them with heavy weapons – something Moscow denies.
Sartana and Lebedynske villages on the eastern outskirts of Mariupol, came under heavy rebel fire, the Kiev authorities said.
They said two Ukrainian troops and two civilians were killed by the rebel shelling.