WASHINGTON - US President Barack Obama and German Chancellor Angela Merkel discussed a significant rise of violence in eastern Ukraine during a call on Tuesday, the White House said.

The two leaders expressed concerns about Russia's material support for the separatists and its failure to fulfil its commitment under the Minsk agreement, and they agreed on the need to hold Russia accountable for its actions, a White House statement said.

"They also agreed on the importance of finalizing a robust package of financial support for Ukraine to enable it to stabilize its economy as it continues to implement reforms that will lay the groundwork for a return to growth and prosperity," said the statement.

Marked by Saturday's shelling in the Ukrainian port city of Mariupol, which claimed at least 30 lives, situation in Ukraine worsened amid a new wave of escalation.

Russian Foreign Minister Sergei Lavrov said Monday that Moscow is taking efforts to revive the peace process in Ukraine.

"We are convinced that the peace process needs to be revived and necessary efforts are being taken for this, primarily to start a full-fledged, sustainable and direct dialogue between Kiev government and insurgents," Lavrov told reporters after meeting with his Israeli counterpart Avigdor Liberman.

He blamed the West for "chronic custom" to accuse Russia and Ukrainian insurgents of everything that happened in the conflict areas, citing Saturday's deadly shelling of the Ukrainian port city of Mariupol as a fresh example, which killed at least 30 people and injured almost 100 others.