"On April 16, the Federal Security Service apprehended Ukrainian diplomat - consul of the Ukrainian General Consulate in St. Petersburg Alexander Sosonyuk red-handed upon receiving classified data from the databases of Russian law-enforcement agencies and the FSB," the press office said in a statement, TASS reported.
As the FSB stressed, "this activity is incompatible with the status of the diplomatic employee and is of clearly hostile nature towards the Russian Federation."
Russia will apply measures to the apprehended Ukrainian diplomat in accordance with international law, the FSB press office said.
Under international law, diplomats enjoy diplomatic immunity in the countries where they work but can be deprived of the right of staying in the receiving state if they breach the law or commit hostile actions.
As follows from the Vienna Convention, the receiving state may at any time notify the sending state that the head of the mission or any member of the diplomatic staff of the mission is persona non grata and the diplomat's stay in the country is not acceptable.