Russian security forces have discovered a homemade bomb in the Moscow apartment of a man linked to the St.Petersburg terror attack.

Officers raided the home of Muhammadyusup Ermatov after arresting his brother Ibragimzhon on Thursday, Russia's Interfax news agency reported. Both men are being held for terror offenses.

Prosecutors told Moscow's Basmanny Court that police had uncovered a bomb made from a fire extinguisher, similar to the device detonated on the St. Petersburg metro on April 3.