ST. PETERSBURG, Russia >> St. Petersburg residents on Tuesday laid flowers outside the city’s subway where a bomb blast a day earlier killed at least 11 people and wounded more than 40. Thousands of miles to the east, authorities in the former Soviet republic of Kyrgyzstan identified one suspect as a Kyrgyz-born Russian citizen.

There was no immediate claim of responsibility for the attack, which came while President Vladimir Putin was visiting the city, Russia’s second biggest and Putin’s hometown.

Kyrgyzstan’s State Committee for National Security said in a statement that one suspect behind the bombing is a Kyrgyz-born Russian national it identified as Akbarzhon Dzhalilov. The Kyrgyz intelligence agency said Russian authorities informed them about the man, aged between 21 and 22, but they were not aware of his specific role in the bombing. The intelligence agency said it is cooperating with Russian authorities to help the investigation.

Neither authorities in Russia nor in Kyrgyzstan have specified whether the attack was a suicide bombing or whether the bomber got away. The Interfax news agency on Monday said authorities believe the suspect was linked to radical Islamic groups and carried the explosive device onto the train in a backpack.

St. Petersburg, like Moscow, is home to a large diaspora of Central Asian migrants who flee poverty and unemployment in their home countries for jobs in Russia. While most Central Asian migrants in Russia have work permits or work illegally, thousands of them have received Russian citizenship in the past decades.

Russian authorities have rejected calls to impose visas on Central Asian nationals, hinting that having millions of jobless men across the border from Russia would be a bigger security threat.

In the past two decades, Russian trains and planes have been frequent targets of attack, usually blamed on Islamic militants. The last confirmed attack was in October 2015 when Islamic State militants downed a Russian airliner heading from an Egyptian resort to St. Petersburg, killing all 224 people on board.

Within two hours of the blast, authorities had found and deactivated another bomb at another busy station, the anti-terror agency said. That station is a major transfer point for passengers on two lines and serves the railway station to Moscow.

The entire St. Petersburg subway system was shut down and evacuated, but partial service resumed after about six hours.