Ukraine crisis: Putin calls on separatists to postpone Donetsk referendum and claims Russia is withdrawing troops from border

Pro-Russian separatists in the eastern region plan to hold a referendum to break free from Ukraine

The Russian president Vladimir Putin has called on separatists in eastern Ukraine to postpone a referendum on the status of the mostly Russian-speaking region.

The Russian Interfax news agency is reporting that Russia has withdrawn troops from its border with Ukraine.

"We're always being told that our forces on the Ukrainian border are a concern. We have withdrawn them. Today they are not on the Ukrainian border, they are in places where they conduct their regular tasks on training grounds," Mr Putin was quoted as saying.

But Nato said there has been no indication Russia troops have been withdrawn.

Separatists in the eastern Donbass region have said they will consider Mr Putin's request not to hold a referendum on secession on 11 May, similar to the one that preceded Russia's annexation of Crimea.

His request came as John Kerry denounced efforts of pro-Russian separatists to hold a referendum on secession as “contrived and bogus” amid fears Moscow plans to split the country by annexing further parts of Ukraine.

"Tomorrow we will discuss that at the people's assembly," Denis Pushilin, a leader of the self-declared Donetsk People's Republic, told Reuters. "We have the utmost respect for president Putin. If he considers that necessary, we will of course discuss it."

Ahead of the votes in the eastern Ukrainian regions of Donetsk and Luhansk on Sunday in which they plan to break free from the rest of the country, the US Secretary of State warned the regions were set to follow the same path as Crimea.

"We flatly reject this illegal effort to further divide Ukraine," the US Secretary of State told reporters after meeting at the State Department with EU foreign policy chief Catherine Ashton. "Its pursuit will create even more problems in the effort to try to de-escalate the situation."

“This is really the Crimea playbook all over again, and no civilized nation is going to recognise the results of such a bogus effort."

The rebel stronghold of Donetsk has become the scene of violent clashes between pro-Russian militants and Ukrainian riot police, with 26 people needing medical attention on Thursday after street battles broke out.

Earlier that day, crowds of pro-Russian supporters had marched through the city demanding the 11 May referendum take place.

Mr Kerry’s comments came as government forces attempted to re-take a city hall in the eastern port of Mariupol, Ukrainian media announced on Wednesday, after heavy fighting with militants.

Mr Kerry warned the US would impose more powerful sanctions designed to hurt Russia's economy if it tries to disrupt Ukraine's presidential election set for 25 May.

"There's no question about our ability, when we want to, to be able to put sanctions in place that are even more biting than what we have today," he continued.

Additional reporting by agencies