Blasts In Saint Petersburg Metro 

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.

According to a Reuters report, Russian President Vladimir Putin, who is in St. Petersburg for a meeting with Belarussian leader Alexander Lukashenko, said the cause of the blasts was not clear and efforts were underway to find out.

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.

(This report will be updated as more further information is made available)