Moscow has reported dozens of sabotage attacks on Russian soil since it sent troops into Ukraine more than two years ago, mostly blaming Kiev and its supporters.

The suspect, in his forties, was found “placing unknown objects in construction waste” near a train station in the centre of Tambov, the FSB said.

Further inspection of the items revealed they were “two homemade explosive devices” which the man planned to detonate near two court buildings in the city, he claimed.

“He was detained by a security guard who arrived at the scene and an operational and investigative team of the Federal Security Service was called in,” the statement said.

According to the FSB, the suspect regularly visited pro-Ukrainian websites and was recruited by Ukrainian special services to carry out the attack earlier this year.

Ukraine regularly denies responsibility for sabotage attacks inside Russia, pointing instead to domestic unrest and domestic opposition to the conflict, now in its third year.