MOSCOW (Reuters) - An explosion in the St Petersburg metro system on Monday has killed at least 10 people, according to “preliminary information,” Russian news agency TASS reported.

A Reuters witness saw eight ambulances near the Sennaya Ploshchad metro station.

Another agency, RIA Novosti, said there appeared to have been blasts at two metro stations.

Three metro stations have been closed, local media outlet Fontanka reported.