At least seven people, including two children, were killed in Russia on Tuesday when a gas explosion caused part of a block of flats to collapse, officials said.

"Due to the explosion, one section of a five-story residential building collapsed" in the city of Yaroslavl north of Moscow, the regional emergencies ministry said in a statement.

"Five flats have been completely destroyed. Seven people died, including a teenager and a five-year-old child," it said. The incident happened around 4:20 am.