Fourteen people remain missing from a fire that claimed a student's life in Ukraine's southern port city of Odessa, President Volodymyr Zelensky said Thursday.

The fire broke out in a college building in central Odessa on Wednesday, killing a 16-year-old female student and injuring 27 others.

The blaze had been contained by Thursday morning, but dozens of firefighters were still combing through the partly destroyed walls of the six-storey building.

Zelensky wrote in a Facebook post: "We all hope that of the 14 missing people, as many as possible will be found safe and sound. But I do not want to deceive anyone -- there may be more victims."

The blaze had been contained by Thursday morning, but dozens of firefighters were still combing through the partly destroyed walls of the six-storey building
The blaze had been contained by Thursday morning, but dozens of firefighters were still combing through the partly destroyed walls of the six-storey building AFP / Oleksandr GIMANOV

Seven firefighters were among the injured and five people were in a serious condition.

"We all are praying" for them, said Zelensky, 41. "We know that doctors are doing everything possible to save them. And impossible too."

The authorities have opened a probe into the blaze.

The mayor of Odessa said the city would observe two days of mourning on Thursday and Friday.