At least 19 people were killed in an explosion at a clinic in Iran’s capital Tehran, officials said.
Several people were injured at the Sina Athar clinic and there are fears that the death toll will rise further.
Iranian state media quoted senior officials as saying the explosion was caused by a gas leak.
Television images showed plumes of smoke rising in the sky. Firefighters extinguished the fire several hours later.
Most of the victims of Tuesday’s explosion were women, officials said.
Some of the victims “were on the upper floors, in the operating rooms – who were operated patients or with them,” said Tehran fire department spokesman Jalal Maleki, according to state media.
“Unfortunately, they lost their lives due to the heat and thick smoke,” he said, adding that the firefighters rescued 20 people.
The clinic, which carries out minor surgery and medical imaging, had 25 employees at the time of the explosion, Maleki said.
The incident occurs several days after a major explosion near a military facility in Tehran.
The cause of this incident was also considered by the authorities to be a gas leak.