Russian officials rule out attack in building collapse Russian authorities are denying reports that a terrorist attack was to blame for an explosion that killed 39 people

MOSCOW -- Russian authorities are denying reports that a terrorist attack was to blame for an explosion that brought down an apartment block, killing 39 people.

The explosion ripped through a building in the city of Magnitogorsk in the Ural mountains on Dec. 31. Sparse official reports and a security incident the following day fed speculation that the explosion was a targeted bombing.

The Islamic State weekly online newspaper al-Nabaa in its Thursday issue claimed responsibility for the explosion in Magnitogorsk, saying that it did not do so earlier for security reasons.

The Russian Investigative Committee on Friday denied the reports, saying that it believes a gas leak to be the likeliest cause of the explosion. The investigators said they found no traces of explosives at the scene.