Suspected accomplices of the man believed to have carried out the St Petersburg metro bombing have been arrested, according to Russian news agency Interfax.

Links between those arrested and the bomber are still being investigated, the agency said, but added that "clues" had been found at the suspected accomplices' addresses.

Monday's explosion killed 14 people, including the bomber, and injured 55 others.

Kyrgyzstan-born Akbarzhon Dzhalilov, 22, has been identified as the man behind the attack.

Seven suspected IS recruiters have been arrested by authorities investigating the explosion, but officials found no immediate evidence of their involvement in the attack.