MOSCOW, March 7 (Xinhuanet) -- A huge explosion ripped through an apartment block in southern Moscow early Sunday morning, injuring at least three people and burying many others under the rubble, Russian news agencies reported.

    At least three people has been injured in the pre-dawn blast, which occurred at around a.m. (0100 GMT), the RIA Novosti news service quoted an official with the Moscow office of the emergencies ministry as saying.

    Earlier, the Itar-Tass news agency reported that several children are among those trapped under the rubble.

    So far, there has been no official comment on what caused the explosion.

    The Interfax news agency reported, quoting a local police official, that the incident might have been caused by a gas leak.

    However, as Itar-Tass reported, police said that an explosive device had been placed on the fourth floor of the building before the explosion.

    At least 8 apartments of the 12-storey building were destroyed and collapsed during the explosion at Chertanovsky Street on the southern edge of the Russian capital.

    It remains unclear whether any one has been killed in the incident, according to the police, who have begun evacuating people from the blast scene.

    The latest incident came just one week ahead of the presidential elections to be held on March 14 as security had been stepped up for the event around Moscow and across the country. Enditem