A suicide bomber from Kyrgyzstan was behind the explosion that killed 14 people and injured dozens more in the Saint Petersburg metro.

A spokesman for the country’s security services told AFP the suicide bomber was Akbarjon Djalilov… Born in 1995,”

He said it is probable that he acquired Russian nationality.

Russia’s investigative committee said it was probing an “act of terror” over the blast that rocked the metro in the country’s second city on Monday afternoon, but added it would look into all other possible causes of the blast.

There was no immediate claim of responsibility for the explosion, which comes after the Islamic state group called for attacks on Russia in retribution for its military intervention in Syria against the jihadists.

Kyrgyz state media said the country’s security service was “Maintaining contact with the Russian secret service for further investigation”.

Authorities in St Petersburg have declared three days of mourning.

Russian President Vladimir Putin, who was in St Petersburg – his home city – when the blast occurred, visited the scene on Monday evening and laid flowers at a makeshift shrine.

Russian investigators have given few details. No group has said it was responsible.

World leaders rallied behind Russia in condemning the blast.

The white house said President Donald Trump had spoken to Mr Putin by phone and offered “full support” in bringing those responsible to justice.

German Chancellor Angela Merkel described the blast as a “Barbaric Act” and EU foreign policy chief Federica Mogherini said Europe’s thoughts were with the Russian people.