A Russian military serviceman was killed on Thursday morning when a bomb exploded under his car in a suburb of St. Petersburg, investigators said, in the second such attack on a Russian officer in the same neighbourhood in less than three months.

The explosion went off at about 7 a.m. local time on Kolpinskoye Highway in Shushary, in the city's Pushkinsky District, as the officer drove out of a residential courtyard, according to the local outlet Fontanka. Russia's Investigative Committee confirmed that a member of the armed forces had died in a vehicle explosion and said it had opened a criminal case on suspicion of murder. The committee did not name the officer or confirm his rank.

Fontanka reported, citing a source, that the dead man was a colonel, and the St. Petersburg outlet 78.ru reported he was a colonel in Russia's 6th Air Force and Air Defense Army, with Lenta.ru reporting he was the army's chief navigator. Reuters said it could not independently verify the rank. Fontanka reported the explosive device had been attached to the underside of the vehicle and detonated remotely.

The killing follows a near-identical attack on August 27, when a car carrying a Russian lieutenant colonel and his wife exploded on the same highway in Shushary, killing the officer and seriously injuring his wife. Russia has blamed Ukraine for previous assassinations of senior military officials and people linked to its war effort. No one had claimed responsibility for Thursday's explosion, and there was no immediate comment from Ukrainian officials.