Six people died after a fire broke out in a psychiatric hospital in Ukraine's Odessa city, the country's State Emergency Service said on Tuesday.

The roof of the medical facility building caught fire on Monday evening, Xinhua news agency reported.

The facility provided mental health care for veterans of the Soviet Union's 1980s war in Afghanistan and World War II, reports said.

"Firefighters rescued 15 people and passed them over to emergency teams. Medics failed to bring back to life four of them who were unconscious," the emergency service said in a press release.

"Later, we received the information about the deaths of two more people," it added.

The police have opened a criminal investigation into the incident, according to the General Directorate of the National Police in the Odessa region. IANS