An oxygen line has exploded at Kommunarka, Moscow’s main coronavirus treatment center, on Wednesday, city authorities said.

Video posted to social media showed clouds of white steam rising from the hospital, which is currently treating 733 coronavirus patients. The RBC news website quoted eyewitnesses as saying that they saw the smoke following a loud bang.

In a statement shortly after the explosion, the Moscow health department said that an oxygen line was depressurized during installation at a temporary ward that is still under construction. The department added that there is no threat to patients or hospital staff.

The state-run TASS news agency cited an unnamed source as saying that the hospital’s operations were not disrupted by the explosion.

The Mash Telegram channel reported, without citing sources, that one hospital employee was injured but is in “satisfactory” condition. It added that 83 patients from three temporary hospital buildings have been evacuated to the main hospital building.

No victims have been reported.