Together more than 30 people were killed in the explosions, putting the city of one million on edge and highlighting the terrorist threat Russia is facing as it prepares to host February’s Winter Olympic Games in Sochi, President Vladimir Putin’s pet project.
British Olympic chiefs are monitoring the safety and security situation in Russia after the second suicide bomb hit the city.
The British Olympic Association (BOA) described the terror attacks as “a painful reminder of the threats that exist in our world today”.
The BOA passed on its “deepest condolences” to the people of Volgograd while also stating its belief that the 2014 Sochi Olympics will be “as safe as possible”.
“As with every Olympic Games – winter and summer – it is the responsibility of security officials at the national level, working in close coordination with regional and local authorities and the Games Organising Committee, to ensure that the environment is as safe and secure as possible,” a spokesman said.
“Throughout their planning for the 2014 Olympic Winter Games, Russian officials have indicated that security would be among the highest priorities, and everything we have seen in their planning would indicate this is the case.
“We are monitoring the situation in Volgograd closely and remain in regular communication with the Foreign and Commonwealth Office, the Met Police, the International Olympic Committee and other relevant bodies.
“Our preparations for the Sochi 2014 Olympic Winter Games continue and we are confident the Russian officials will regularly assess the security measures that are in place.”
Volgograd, about 650 kilometres (400 miles) north east of Sochi, serves as a key transport hub for southern Russia, with numerous bus routes linking it to volatile provinces in Russia’s North Caucasus, where insurgents have been seeking an Islamic state.
The city, previously called Stalingrad, also serves as an important symbol of Russian pride because of a historic Second World War battle in which the Soviets turned the tide against the Nazis.
Vladimir Markin, the spokesman for Russia’s main investigative agency, said yesterday’s explosion involved a bomb similar to the one used in Sunday’s suicide attack at the city’s main railway station.
“That confirms the investigators’ version that the two terror attacks were linked,” Mr Markin said in a statement.
“They could have been prepared in one place.”
Mr Markin said a suicide attacker was also responsible for the bus explosion.
No one has claimed responsibility for either bombing, but they came several months after Chechen rebel leader Doku Umarov threatened new attacks against civilian targets in Russia, including the Winter Olympics.
A suicide bus bombing in Volgograd in October killed six people.
On Friday, three people were killed when an explosives-rigged car blew up in the city of Pyatigorsk, the centre of a federal administrative district created to oversee Kremlin efforts to stabilise the North Caucasus region.