KIEV (Reuters) - Ukraine's new rulers announced on Sunday a call-up to raise 20,000 men for a newly-created National Guard, accusing Russia of sending "touring" trouble-makers across the border to stir up separatism in the country.
Keeping tension high as pro-Russian Crimean leaders staged a referendum for the peninsula to secede to Russia, Prime Minister Arseny Yatseniuk vowed to bring to justice all those who were trying to destroy Ukrainian independence "under the cover of Russian troops".
Earlier, acting defence minister Ihor Tenyukh said Russia was pressing ahead with a military build-up in Crimea in violation of an agreement covering basing rights for its Black Sea fleet which has been there since Soviet times.
Instead of an agreed limit of 12,500 Russian servicemen in Crimea, Moscow now had 22,000 there, he said. "This is a crude violation of the bilateral agreements and is proof that Russia has unlawfully brought its troops onto the territory of Crimea," Tenyukh said.
He later told journalists that the defence ministries in Kiev and Moscow had declared a truce until March 21 during which Russian forces, who have been arriving by boat and helicopter, would leave Ukrainian military facilities untouched.
Yatseniuk, just returned from a trip to the United States where he won expressions of moral support but no offers of weapons, urged Ukrainians to sign on for service with the embryonic National Guard.
"It (the National Guard) will have training centres, legal weapons will be distributed. You will have the opportunity to defend the country, with the forces of the National Guard and the security forces," he told a cabinet meeting.
He had a harsh warning for separatist "ringleaders" who stirred up division in the ex-Soviet republic and were trying to destroy Ukrainian independence "under the cover of Russian troops".
"We will find all of them - if it takes one year, two years - and bring them to justice and try them in Ukrainian and international courts. The ground will burn under their feet," he said.
Interior Minister Arsen Avakov said half the strength of the National Guard was being sought within a fortnight. "About 10,000 will be called up in the next 15 days," he said.
Apart from Crimea, tension is also running high in parts of the Russian-speaking industrialised east of the country near the border with Russia, with clashes between rival demonstrators which Moscow has seized on to support its case that ethnic Russians are being victimised in Ukraine.
Two pro-Russian demonstrators were killed in Kharkiv on Friday night and one pro-Ukrainian activist was killed in Donetsk the night before.
In Donetsk on Sunday activists, angry about the detention of a pro-Moscow local leader, broke into the prosecutor-general's office and raised the Russian flag. About 500 of them later broke windows at the local headquarters of the state security service but were held back from entering the building.
Remarks by Kremlin leader Vladimir Putin and other high-ranking Russian officials that Moscow reserves the right to protect its compatriots and Russian-speakers in Ukraine have aroused fears in Kiev that Russia could be preparing broader military action against Ukraine beyond just Crimea.
But Avakov poured scorn on this argument on Sunday. "These people are professional touring provocateurs from a neighbouring country," he said, saying they were the same people who had been stirring up trouble at pro-Russian rallies in the Baltic states in 2009.
He said that Ukrainian border guards and some members of the national Guard had now virtually sealed off parts of the eastern border with Russia to prevent people "with doubtful intentions" coming in. "Every day we are detaining hundreds of these people," he said.
Yatseniuk said the government had agreed to earmark 6.8 billion hryvnia (about 408 million pounds) for extra defence spending over the next three months though, in all, Ukraine would need 10 times the normal amount set aside for defence spending in the budget.
(Additional reporting by Ron Popeski; Writing by Richard Balmforth; editing by David Stamp)