UK & World News
Volgograd: At Least 14 Dead In Bus Bombing
At least 14 people have reportedly died in an explosion on an electric bus in the Russian city of Volgograd in the second deadly attack in the city in as many days.
Investigators have described the blast, during the morning rush-hour on a trolleybus, as "an act of terror".
Russian investigators said the bus explosion was caused by a male suicide bomber.
A statement from the Federal Investigative Committee said: "It is now possible to preliminarily say that the explosive device was set off by a suicide bomber - a man whose body fragments have been collected and sent for genetic testing."
It comes just a day after a female suicide bomber was blamed for killing 17 people and leaving dozens more injured at the city's main railway station.
Police identified that bomber as a Dagestan national called Oksana Aslanova - who had been married to two Islamists killed by Russian forces.
She apparently detonated a bomb in front of a metal detector inside the main entrance of the station. Russian television is suggesting there may have been two attackers.
That attack was the deadliest in Russia since January 2011, when a male suicide bomber from the North Caucasus killed 37 people in the arrivals hall of a busy Moscow airport.
Vladimir Markin, a spokesman for Russia's main investigative agency, said the latest explosion involved a bomb similar to the one used to target Volgograd railway station. The bomb contained 4kg of TNT equivalent explosive.
He said: "That confirms the investigators' version that the two terror attacks were linked. They could have been prepared in one place."
President Vladimir Putin has ordered Russia's counter-terrorism agency to step up security in Volgograd and nationwide in the wake of the two attacks, the Kremlin announced.
The explosions have put the city on edge and highlighted the terrorist threat that Russia is facing as it prepares to host the Winter Olympics in February.
Volgograd is about 400 miles northeast of Sochi, where the Games are to be held.
There was no immediate claim of responsibility for either of the attacks.
In July, Doku Umarov, leader of an ongoing insurgency in the nearby North Caucasus region, urged militants to use "maximum force" to disrupt the Winter Olympics, a project close to Mr Putin's heart.
Russian authorities have pledged to make the event the "safest ever".
Sky's Foreign Affairs Editor Tim Marshall said: "It's 39 or 40 days until the Winter Olympics open, this is the opportunity for the Islamic separatists in the Caucasus region to really put themselves on the world map.
"The more this sort of thing happens, if it is indeed them, the more that cause is going to get on the front pages around the world, spoil Putin's Olympics and, more seriously, the more lives it will take."
Known in Soviet times as Stalingrad, and previously as Tsaritsyn, Volgograd is a major industrial centre with a population of more than a million people.
The North Caucasus is the region between the Black Sea and the Caspian Sea, bordered by Georgia and Azerbaijan to the south.
It includes the predominantly Muslim Krasnodar Kai, Stavropol Krai, Adygea, Karachay-Cherkessia, Kabardino-Balkaria, North Ossetia, Ingushetia, Chechnya and Dagestan.
Insurgents have carried out attacks on Russian military and civilians following two wars against Chechnya in 1994-1996 and from 1999 to 2009.
The violence has spread into neighbouring republics and even Moscow as insurgents attempt to establish an Islamic state in the region.
:: Watch Sky News live on television, on Sky channel 501, Virgin Media channel 602, Freeview channel 82 and Freesat channel 202.