MADRID (Reuters) - A group of unidentified men entered North Korea's embassy in Madrid last Friday, bound and gagged staff, and drove off four hours later with computers, according to a report by the El Confidencial news site, broadly confirmed on Wednesday by a Foreign Ministry source.

The Interior Ministry officially said police were investigating an incident, but gave no details except to say that a North Korean citizen had been injured and that no one had filed a complaint.

El Confidencial said one of the staff had managed to free herself and escape, alerting neighbors with screams in Korean.

After she told police that staff were being held, gagged, they knocked on the door to investigate, and a man told them everything was fine. But soon after, two cars left the compound at high speed, one of them carrying the man who had answered the door. The staff walked out of the building soon after.

The website said the attackers had taken away computers belonging to various staff members, and that police were trying to find out what information they might have contained, and what else might be missing.

"Basically, the information that El Confidencial describes is how the events unfolded," the Foreign Ministry source said.

An Interior Ministry source told Reuters that police were not ruling out any motive, including robbery.

Spain was among a group of countries that expelled North Korean ambassadors in 2017. The interior and foreign ministry sources said the highest-ranking North Korean official accredited in Spain was a trade attache.

Reuters could not reach any representative of North Korea in Spain. El Confidencial said it had contacted an official, who declined to comment.

The Foreign Ministry told Reuters: "We have been in close contact with the Embassy and we were notified by the police at the outset ... The police investigation in progress and we cannot comment on it."

(Reporting by Belen Carreno and Andres Gonzalez; Writing by Ingrid Melander; Editing by Kevin Liffey)