Russian police have discovered an explosive device at an apartment in St Petersburg, just three days after a bomb was detonated on the city's metro system, killing 14 and injuring dozens more.

Several suspects were arrested after police raided the flat and made the device safe, according to the Investigative Committee of Russia. The police raid followed the arrest of six suspects on 5 April, who are being held on suspicion of recruiting for Isis and involvement in terrorist activity.

More from IBTimes UK

The main suspect in the metro bombing, Kyrgyz-born Russian citizen Akbarzhon Jalilov, died in the attack. His parents identified his remains on 5 April.

The apartment was raided at around 05:00 local time (01:00 GMT) this morning (6 April) in Tovarichesky Prospekt, in the east of St Petersburg. Sources told Interfax news agency that investigators are examining links between the suspects and Jalilov, who rented an apartment in the city a month before carrying out the attack.

The Investigative Committee of Russia said that the suspects were all "citizens of Central Asian Republics" and that "objects of importance for the investigation" were found at the apartment.

Russian newspaper Fontanka shared an image of police escorting the suspects into custody. Residents living in the apartment building were evacuated to a kindergarten nearby.