At least two explosions have been heard in a residential building in St. Petersburg cordoned off by National Guard and security forces, local media reported. They were followed by plumes of smoke, witnesses added.
Photos on social media show dozens of police cars and heavily-armed officers around the building.
The officers haven’t evacuated the building, witnesses told Fontanka media outlet, adding that officers aren’t letting anyone into the building either. “Small groups of Special Forces are emerging from the entrance, while others go inside,” a witness told Fontanka.
An official from Federal Security Service told RIA Novosti the agency is conducting an operation to detain suspected North Caucasus militants. The operation is underway in an apartment block “to detain individuals who are on a federal wanted list and are accused of taking part in illegal armed gangs in the North Caucasus region,” the local FSB press service said, as cited by TASS.

Source: RT.com