The United States is prepared to impose new sanctions on Russia, president Barack Obama has told four European leaders.
The White House said the allies agreed Russia has not abided by an agreement to ease tensions with Ukraine and has escalated strains in the eastern parts of the former Soviet state.
Mr Obama spoke with Prime Minister David Cameron, French president Francois Hollande, German chancellor Angela Merkel and Italian premier Matteo Renzi, the White House said.
Mr Obama placed the conference call while in South Korea, the second stop of a four-country Asian trip.
The leaders agreed Russia has not lived up to an agreement signed in Geneva last week by using worrisome rhetoric and threatening military exercises on Ukraine's border, the White House said.