Russia said on Thursday it had arrested two suspects linked to two suicide bombings last month in the city of Volgograd that left 34 people dead, and that it had identified the two bombers, dpa reported.
The city is in the Northern Caucasus region 700 kilometres north of Sochi, where the Winter Olympics games are to begin on February 7. Militants there have vowed attacks against the Games.
The National Anti-Terrorism Committee said the people who carried out the attack belonged to a group of radical Islamist militants.
Security chief Alexey Lavrichev told reporters at Olympic Park on Thursday that everyone is safe and there is no imminent terror threat to the games.
"The situation is under control," he said.
Some 40,000 security forces are to safeguard the first Winter Games in Russia.