An explosion that Russian officials blamed on gas has devastated an apartment building in a southern Russian city, sending eight people to the hospital and leaving about 150 residents homeless.

The blast in Volgograd, 900 kilometers (550 miles) southeast of Moscow, occurred about midday Sunday in an apartment on the seventh floor of the nine-story structure. Much of the building's exterior wall on one side was blown off and fire spread to other floors.

Health Ministry official Sergei Goncharov was quoted by Russian news agencies as saying eight people were hospitalized with medium or light injuries.

About 150 people lived in the section of the building affected by the blast, said Vladimir Markin of the Investigative Committee. Those forced to leave were being housed in a local school.