It was unclear what the target of the strike was, though Libyan officials said it was Muammar Gaddafi himself, who was giving a live television address at the time.

"They maybe wanted to hit the television. This is a non-military, non-governmental building," said Mohammed al-Mehdi, head of the civil societies council, which licenses and oversees civil groups in Libya.

The missile completely destroyed an adjoining office in the compound that houses the government's commission for children.

The force of the blast blew in windows and doors in the parent-funded school for children with Down's Syndrome and officials said it damaged an orphanage on the floor above.

"I felt sad really. I kept thinking, what are we going to do with these children?" said Ismail Seddigh, who set up the school 17 years ago after his own daughter was born with Down's.

"This is not the place we left on Thursday afternoon."

There were no children at the school when the missiles hit early on Saturday morning, since Friday begins the weekend in Libya. Children had been due to come in on Saturday morning.

A mound of rubble was all that remained of one wing of the main building that adjoined the school, though an antenna of some kind protruded from the ruins.

Both Mehdi and Seddigh said they had assumed that the antenna on the building was there to strengthen mobile phone signals and were not aware of any other use.

In the rubble of the main building, a shredding machine packed with sliced up documents lay on its side. A fax and phone were nearby and shelves of files could be seen.

The Libyan government has repeatedly said that NATO airstrikes have hurt and killed civilians but has not responded to requests by journalists to visit the hospitals, making it tough to verify casualty figures.

NATO has hit inside or near Gaddafi's compound before, or struck military or logistical sites. Saturday's government-organized visit was the first to bring journalists -- whom government minders watch closely -- to a civilian site.

Inside the school, the power had been knocked out by the strikes, the floor was wet because of a leaking pipe and desks were covered in glass and debris.

Seddigh's school prepared children with Down's Syndrome up to the age of 6 to go to normal schools, giving them speech therapy, handicrafts and sports sessions and teaching them to read and write. It handles 50 to 60 children a day.