German Chancellor Angela Merkel and Russian President Vladimir Putin have agreed to do everything necessary to keep violence in Ukraine from getting worse, the chancellor said.

Merkel said she had spoken to Putin by telephone and "we agreed to continue to do everything so that there is no escalation of violence".

"I informed him that French, German and Polish foreign ministers planned to go to Kiev tomorrow," Merkel said on the sidelines of a meeting with French President Francois Hollande in Paris.

"We decided to keep very close contact with Russia."