WASHINGTON - The leaders of the Group of Seven major economies agreed on Saturday to move swiftly to impose further sanctions on Russia over the Ukraine crisis, and the United States could unveil its new punitive measures as early as Monday, officials said.

A senior US official said each G7 country would decide which targeted sanctions to implement and while the measures would be coordinated they would not necessarily be identical.

The new sanctions are intended to punish Russia for failing to comply with an international agreement to help defuse the Ukraine crisis, according to a statement from G7 leaders released by the White House while President Barack Obama was on a visit to South Korea.

"Given the urgency of securing the opportunity for a successful and peaceful democratic vote next month in Ukraine's presidential elections, we have committed to act urgently to intensify targeted sanctions and measures to increase the costs of Russia's actions," the statement said.

The statement did not specify what new measures would be slapped on Moscow but it warned that "we continue to prepare to move to broader, coordinated sanctions, including sectoral measures should circumstances warrant."

At the same time, the leaders told Russia that "the door remains open to a diplomatic resolution of this crisis" and urged , on the basis of the Geneva accord. We urge Russia to join us in committing to that path.