Russia expels Ukrainian diplomat after detaining him amid border tensions

Russia on Saturday expelled a Ukrainian diplomat who it said was caught "red-handed" trying to obtain sensitive information. Although Russia has detained a number of Ukrainian nationals in recent years, expulsion of a diplomat is rare and is being seen as sign of sharply rising tensions between the two countries.

"A Ukrainian diplomat, a consul of Ukraine's Consulate General in Saint Petersburg, Alexander Sosonyuk, has been detained by Russia's FSB," the security service said in a statement, using the Russian language spelling of his name.

The diplomat was detained on Friday, the security service said. Kiev said the diplomat had spent several hours in detention.

Russian foreign ministry said later on Saturday that it had summoned Ukraine's charge d'affaires Vasyl Pokotylo and told him that the Ukranian diplomat had 72 hours to leave the country "beginning April 19"

"The Russian side pointed to the inadmissibility of such kind of activity," the foreign ministry said in a statement.

Russia's domestic intelligence agency said that Sosnyuk had been caught "red-handed" during a meeting with a Russian national as he sought to receive "classified" information. 

"Such activity is not compatible with his diplomatic status and is of clearly hostile nature towards the Russian Federation," the FSB said.

Tensions between Russia and Ukraine have seen sharp escalation in recent weeks. On Saturday, Russia reinforced its naval presence in the Black Sea by sending two warships. These ships are capable of carrying tanks and troops for assault landings.

Ukraine has been accusing Russia of having built up military presence on its borders to destroy "Ukrainian statehood"

Moscow claims that the troop build-up is defensive in nature.

(With inputs from agencies)