A fire at a psychiatric hospital in southern Russia has killed 23 people, the country's emergencies ministry has said.

The hospital building, which was made of wood, was destroyed by the fire, a spokesman said.

A further 20 people were injured.

The fire broke out at the hospital in the village of Alferovka, which lies in the southern region of Voronezh.

More than 440 firefighters and emergency workers spent around three hours bringing the fire under control.

It was not immediately clear what triggered the blaze.

The fire was the latest tragedy to hit a psychiatric institution in Russia, where outdated Soviet-era infrastructure is still in widespread use.

A fire at a psychiatric hospital in northwest Russia in September 2013 left 37 people dead while another blaze in April of the same year killed 38.

In 2009, 156 people were killed in a nightclub fire in the city of Perm, 700 miles east of Moscow.