More than 60 people remain in hospital after two suicide bomb attacks in the city of Volgograd last week, Russia's Health Ministry said on Monday.

      There are 22 people currently being treated in Moscow hospitals and 39 in hospitals in the southern Russian city where the blasts occurred, a ministry spokesperson said.

      The explosions killed 34 people and injured more than 100 when suicide bombers targeted Volgograd’s main railway station on December 29 and a trolleybus in the city on December 30.

      The last attack was the third in the southern city in the past two months, and comes just weeks before Russia is due to host the 2014 Winter Olympic Games in February in the city of Sochi. It has raised security concerns over the Games, which are to take place about 430 miles (690 kilometers) from Volgograd.

      No one has claimed responsibility for the blasts, but an Islamist militant leader in Russia's North Caucasus has threatened to disrupt the Games.