French President Francois Hollande and British Prime Minister David Cameron on Monday called on Ukrainian different factions to show restraint in a bid to find a rapid and peaceful solution to the crisis.

During a phone conversation on the escalating violence in Ukraine after pro-Russian militia seized state buildings in the east of Ukraine, both leaders called for "restraint and dialogue to allow a de-escalation and quickly find a peaceful solution to the crisis."

They also reiterated "their support for the Ukrainian government to carry out the reforms expected by the people and organize the presidential election on May 25 with the best conditions," according to a statement issued by the presidency office, the Elysee.

Earlier in the day, Ukraine's acting president Oleksandr Turchynov threatened military action against pro-Russian protesters after occupying government buildings in the east.

Tensions in eastern Ukraine escalated on Sunday following an armed confrontation between Ukrainian security forces and pro-Moscow protesters, which killed at least one person and injured 10 others.

The new development came after Crimea left Ukraine to join Russia last month.