MOSCOW (AP) — Russia has detained a Ukrainian diplomat for allegedly receiving classified information from a database of the country’s main security agency.

The Federal Security Service, or FSB, said Saturday that Alexander Sosonyuk, Ukraine’s consul in St. Petersburg, was taken into custody on Friday during a meeting with a Russian in which he received “information of a classified nature contained in the databases of law enforcement agencies and the FSB."

The FSB statement, reported by Russian news agencies, didn't give further details.

The detention comes amid escalating tensions between Russia and Ukraine amid a Russian military buildup along the border with the eastern Ukraine region, which is under the control of Russia-backed rebels.