DHAKA: At least 15 people have been killed and 23 others hurt in a suspected terrorist attack on a trolleybus in the Russian city of Volgograd, officials say.

The blast comes a day after 17 people died in a suicide bombing at the central station in the city, reports BBC.

Security has been tightened at railway stations and airports across Russia.

Moscow is concerned militant groups could be ramping up violence in the run-up to the 2014 winter Olympic Games in the city of Sochi.

The Olympic venue is close to Russia`s volatile north Caucasus region.

Volgograd lies about 900km (560 miles) south of Moscow, 650km north of the North Caucasus and 700km north-east of Sochi.

A spokesman for Russia`s Investigative Committee said both explosions were now being treated as acts of terrorism.
Busy market

The latest explosion took place near a busy market in the city`s Dzerzhinsky district during Monday morning rush hour.

The area has been cordoned off, and police and emergency services are at the scene.

Images posted on social media websites showed the burned-out shell of the trolleybus and bodies scattered around.

Sunday`s blast rocked Volgograd-1 station at around 12:45 (08:45 GMT) at a time of year when millions of Russians are travelling to celebrate the New Year.

A nearby security camera facing the station caught the moment of the blast, showing a bright orange flash behind the station`s main doors.

The explosion shattered windows and sent debris and plumes of smoke from the station entrance.

No group has yet said it was behind the blast.

An Islamist insurgency in the North Caucasus region has led to many attacks there in recent years. Insurgents have also attacked major Russian towns.

The attacks show that the bombers do not need to attack Sochi directly to attract international attention - any target in Russia will do, says the BBC`s Daniel Sandford in Moscow.

16 killed in Russia Suicide bombing

BDST: 1155 HRS, DEC 30 , 2013
RS