Ukraine's Security Service (SBU) today said it was detaining 10 "Russian spies" arrested over the past six weeks on suspected missions to stir up unrest in the separatist eastern region of the country.
Such clandestine operators constituted the "main threat" to security in the country, a spokeswoman told a Kiev news conference.
"We have identified 10 Russians with Russian passports and they are now under investigation and they are being detained in Kiev's detention centre," Maryna Ostapenko said in the headquarters of the SBU.
They were arrested after being suspected of having "spying experience," she said.
"The main threat for us now are Russian spy rings. These groups are illegal and can use explosives," she said.
Yesterday, the SBU's counter-intelligence department said 40 Russian spies had been uncovered since early March.
Ostapenko did not explain why that number was revised on Thursday to 10.
In a sign of Kiev's extreme wariness over Russian spooks and saboteurs infiltrating its territory, the Russian airline Aeroflot announced that all Russian males aged 16 to 60 were now being barred entry into Ukraine unless they could prove family imperatives or other pressing reasons to go there.
Ukraine's interim government has repeatedly said that Russian intelligence and special forces are coordinating the insurgencies in Russian-speaking parts of the country.
Russian President Vladimir Putin today for the first time admitted that Russian troops were deployed in the southern peninsula of Crimea before Moscow annexed it last month. He continues to deny, however, that such forces are in action in Ukraine's east.
A spokesman for Ukraine's border service, Oleg Slobodyan, said at the same SBU news conference that measures were being taken to prevent Russian intelligence operatives entering the country.
Five "tactical units" were patrolling Ukraine's eastern coastline on the Azov Sea which is shared with Russia, "in order to prevent spy rings landing," he said.
