A crowd of pro-Russian activists stormed a police station in the town of Horlivka, near Donetsk, taking control of the building and ignoring a deadline to leave or face eviction by Ukrainian forces.

Ukraine’s interim President Oleksandr Turchynov hit out at “aggression” from Russia, but signaled support for a national referendum.

Oleksandr Turchynov said Kiev was “not against” a vote on the future of the country, a key demand from protesters.

He also said Ukraine was preparing an “anti-terrorist operation” against gunmen occupying government buildings in Sloviansk and a number of other towns and cities.

Correspondents say people in eastern Ukraine are anxiously waiting to see if Oleksandr Turchynov carries through on his threat to use the army against the pro-Russian groups.

In a televised address to parliament, President Oleksandr Turchynov suggested Kiev would be open to moving from a republic into a federation and giving broader rights to Ukraine’s Russian speakers.

The pro-Russian groups who have seized government buildings in eastern regions are demanding local referendums on either increased local rights or an option to join the Russian Federation.

But Oleksandr Turchynov stopped well short of giving in to these demands by showing support for a national referendum, of which the outcome is uncertain because most people in Kiev and the Ukrainian-speaking west reject the idea of federalization.

“We are not against holding a national referendum,” he said.

“I am certain that a majority of Ukrainians will support an indivisible, independent, democratic and united Ukraine.”

He also used the speech to accuse Moscow of open aggression in the east of the country.

“It’s not a confrontation between Ukrainians, but covert and now no longer covert aggression by the Russian Federation against our country,” Oleksandr Turchynov added.

Russian Foreign Ministry Sergei Lavrov said it was not in Russia’s interests for Ukraine to break up but added that Moscow wanted all citizens of the country to be given equal treatment by Kiev.

He also denied allegations that Russian agents had been fomenting unrest in eastern Ukraine and said he was seeking explanation from US of reports that CIA director John Brennan had visited Kiev.

At an emergency meeting of the UN Security Council on Sunday, Russia urged Kiev not to use force against protesters in eastern Ukraine.

The Russian Ambassador to the UN, Vitaliy Churkin, called on the government in Kiev to “start a genuine dialogue”.

Vitaliy Churkin warned UN diplomats that there were neo-Nazis and anti-Semites within the ranks of “the self-proclaimed government in Kiev”.

[youtube M2924YB3ZG4 650]

Pro-Russian activists threw rocks at the police HQ in Horlivka before storming it