St Petersburg: A suspected suicide bomber thought to be responsible for a deadly blast in the St Petersburg metro on Monday had links with  radical  Islamist groups banned in Russia, a law enforcement source told Interfax news agency, as Russia opened a probe into a suspected ‘act of terror’.

The source also told Interfax that authorities had established the identity of the suspect: a 23-year-old from Central Asia who had carried an explosive device into the St Petersburg metro in a rucksack.

The source added that remains found at the scene of the blast that killed 11 people and injured more than 40 suggested that a suicide bomber was responsible but that final conclusions would be made after DNA tests had been conducted.

‘All the signs of a terrorist attack are there,’ Viktor Ozerov, head of the security committee in the upper house of parliament, said by phone from Moscow. 

‘The complex of measures against terrorism in the country failed.’

US President Donald Trump, asked about the blast by reporters at the White House, called it a ‘terrible, terrible thing – happening all over the world.’