Six people died when fire swept through a psychiatric hospital for war veterans in the Ukrainian city of Odessa, authorities said on Tuesday.

The fire erupted late Monday evening in the one-storey building, Ukraine’s emergency services said in a statement.

“Six people died and four have been hospitalised,” the statement said. Nine other people escaped unharmed.

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

Police and emergency services did not immediately comment on whether the fire was started deliberately, but said it did not appear to have originated inside the building.

Paramedics continued to search the hospital after the fire had been extinguished, looking for any patients who could have been left behind, an AFP journalist said.

Bodies lay covered on the ground outside the brick building. Fifty-seven firefighters on 12 fire engines fought to extinguish the blaze, emergency services reported.

Ukrainian President Volodymyr Zelensky said he regretted the “terrible tragedy” and ordered Prime Minister Volodymyr Groysman to set up a committee to investigate.

“The reasons (for the fire) will be established. I present my condolences to the families of the victims,” he said on Twitter.

Deadly fires are relatively frequent in Ukraine and other former Soviet republics due to outdated infrastructure and poor security measures.

Separately, Ukrainian President Volodymyr Zelensky on Tuesday defended his position at the Constitutional Court, which is set to rule on the legality of his decision to dissolve parliament and call for early elections.

Zelensky was elected on a wave of popular support amid disillusionment with predecessor Petro Poroshenko. But the former comedian and political novice has struggled to work with lawmakers largely hostile to him.

He announced his intention to dissolve parliament in his inaugural speech on May 21 and signed a decree to this effect shortly afterwards.

As some political analysts called the move unconstitutional, several MPs appealed to the Constitutional Court to decide whether it was legal.

The tribunal has to make its decision by June 29, Zelensky’s team said.

Agencies