The death toll from the bomb blast in St. Petersburg has risen to 14, Russian agency Ria Novosti quoted the country’s health minister Veronika Skvortsova as saying on Tuesday.
The blast which happened on a metro train has also injured almost 50 people.
The death toll stood at 11 people on Monday.
In a related development, Russia Foreign Minister Sergei Lavrov said that the deadly bomb shows the need for joint efforts against global terrorism.
“(This tragedy in St Petersburg) once again shows the importance of stepping up joint efforts to combat this evil,” Lavrov said at a meeting with his Kyrgyz counterpart Erlan Abdyldayev.
The attack which has now killed 14 people is now thought to have been carried out by a man born in Kyrgyzstan.
The St Petersburg television showed footage of the corpse of a bearded man they said was the perpetrator.
The man resembled footage of a man captured on closed circuit television who Russian media said was a suspect.
Officials said they were treating the blast as an act of terrorism, but there was no official confirmation of any link to Islamist radicals.
The National Anti-Terrorist Committee said an explosive device had been found at another station, hidden in a fire extinguisher, but had been defused.
Authorities closed all St. Petersburg metro stations.
The Moscow metro said it was taking unspecified additional security measures in case of an attack there.
The blast raised security fears beyond Russian frontiers.
France, which has itself suffered a series of attacks, announced additional security measures in Paris.