Six people were killed and the seventh was seriously injured in a bus fire early on Tuesday morning in eastern Moscow, Russian Emergency Situations Ministry said.

The seven Uzbek citizens were sleeping in the Mercedes bus as it caught fire at a parking lot at Moscow's ring road at 2:15 a.m.local time, Russia's Interfax news agency quoted the ministry as saying.

Preliminary investigation attributed fire cause to careless handling of combustible materials, the ministry said.

However, the Itar-Tass news agency quoted local firefighting department source as saying that five Uzbek passengers aboard the bus were killed.

The source said a gas cylinder used for cooking food exploded and caused the tragedy. The situation was aggravated as bags blocked the bus exit.

A gas cylinder blast killed 12 Russian people at a big Moscow market in December 2001.

Source: Xinhua