Chinese Foreign Minister Wang Yi on Sunday sent a letter of condolence to his Russian counterpart Sergey Lavrov over the casualties in a fire at a psychiatric hospital in Russia.

The blaze killed more than 20 patients and left dozens injured, the Russian Emergency Situations Ministry said Sunday.

When the fire broke out late Saturday night, over 70 people were inside the hospital in the Russian southwestern Voronezh region.

In the letter, Wang mourned for the victims and expressed deep sympathy for the wounded and the victims' families.