At least 13 people have died in a suicide bomb attack on a railway station in the southern Russian city of Volgograd.
Russia's anti-terrorism committee said a female suicide bomber was responsible for the explosion, which also injured around 50 people.
The bomb exploded at around 12:45pm local time (08:45 GMT). Footage from the scene shows bodies lying on the forecourt of the station.
A suspected female suicide bomber killed at least six people when she attacked a bus in the city in October - one of the deadliest attacks outside the troubled North Caucasus region in more than two years.
Islamist insurgents have been responsbile for several attacks in North Caucasus other Russian towns in recent years.
Russian authorities fear that attacks from militant groups could be on the rise in the lead-up to the the 2014 winter Olympic Games in the city of Sochi, which open on 7 February.
In July, Chechen insurgent leader Doku Umarov posted an online video urging militants to use "maximum force" to stop the Games from going ahead.
Volgograd lies about 690km (430 miles) north-east of Sochi.