Security has been stepped up in Moscow and throughout Russia, following the deadly explosions in Volgograd.

President Vladimir Putin has reportedly issued a series of new measures to Russia’s Anti-Terrorism Committee in an effort to “strengthen security Russia-wide and specifically in the Volgograd region.”

The blasts have heightened fears about public safety throughout the country.

“It’s very painful and scary,” said one passenger in a train station in Moscow.

Extra officers are being deployed to railway stations and airports nationwide.

Reports suggest Sunday’s train station bomber is from Dagestan, the province adjacent to Chechnya and the centre of a long-running Islamist insurgency.

The insurgency is rooted in two post-Soviet separatist wars in Chechnya, the second of which was launched by Putin during his time as Prime Minister. It succeeded in driving separatists from power.

Some experts had already predicted further attacks in southern Russia before the start of the Winter Olympics in February.

“We can expect more such attacks,” Alexei Filatov, deputy head of the veterans’ association of the elite Alfa anti-terrorism unit, said on Sunday.

“The threat is greatest now because it is when terrorists can make the biggest impression,” he added. “The security measures were beefed up long ago around Sochi, so terrorists will strike instead in these nearby cities like Volgograd.”

According to a local police officer in Volgograd, the city’s police force has been depleted in recent months, with some 600 officers redeployed to Sochi to tighten security around Olympic sites.