A pediatric and maternity hospital was severely damaged Wednesday in a Russian airstrike on the encircled Ukrainian port city of Mariupol, injuring at least 17, local official Pavlo Kyrylenko said.

Ukrainian President Volodymyr Zelenskyy posted a video on Twitter showing massive destruction at the large medical complex, including blown-out windows and internal walls ripped out, which he said was caused by a "direct strike by Russian troops."

He said that adults and children were "under the wreckage."

"So far there are 17 wounded personnel of the hospital," Kyrylenko, the head of the southeastern Donetsk region, said later in a video posted on Facebook. He added that "so far no kids were wounded" and there have been no deaths.

Kyrylenko said that the attack "literally destroyed" the maternity hospital in the center of the city that also included a pediatric unit.

He said that a Russian pilot evidently knew where the bomb would land.

Mariupol on the Azov Sea in southeastern Ukraine is surrounded by Russian forces, who have bombarded the city despite promises of a cease-fire to allow civilians to be evacuated.

Videos posted by Kyrylenko and the city authorities showed the evacuation of the hospital including a woman on a stretcher and a woman being supported by two men as she walks out.

They show a huge crater in the yard of the hospital, branches snapped from trees and burning cars, while cladding has been ripped from the building's facade.

Zelenskyy condemned the attack as an "atrocity" and called again for a no-fly zone to be imposed over the country. NATO has refused to do this.

British Prime Minister Boris Johnson also condemned the attack, saying: "There are few things more depraved than targeting the vulnerable and defenseless."

No health facility "should ever be a target," United Nations spokesperson Stephane Dujarric said Wednesday after the apparent Russian airstrike.

The U.N. and the World Health Organization have called for an "immediate halt to attacks on health care, hospitals, health care workers, ambulances," Dujarric said during his daily press conference.

Earlier in the week, the majority of patients in Ukraine's largest children's hospital were evacuated.