SINGAPORE - There have been no reports of Singaporeans injured or directly affected by Monday's blast in Russia's St Petersburg metro, a spokesman for the Ministry of Foreign Affairs told The Straits Times on Monday (April 3) night.

Responding to ST's queries, the spokesman said the Singapore Embassy in Moscow has reached out to Singaporeans who are e-registered in St Petersburg.

All of them are safe, said the spokesman.

"Thus far, there have been no reports of Singaporeans directly affected by or injured in the incident," he said.

The blast, which occurred at about 2.40pm Russian time (7.40pm Singapore time) in between two train stations, killed at least nine people and injured dozens more.

The bomb was said to have been filled with shrapnel, according to Interfax news agency.

All stations along the St Petersburg metro were closed, and Moscow's metro intensified security measures.

A second device that did not detonate was reportedly found at another station in the city, while images of a suspect were reportedly captured on surveillance cameras.

St Petersburg authorities declared a three-day period of mourning after the explosion.