MADRID — The Spanish authorities announced on Wednesday that they had begun an investigation into a possible attack at the North Korean Embassy in Madrid, after one of the embassy employees said she was assaulted.

The episode was said to have happened last Friday, though neither the employee nor the embassy of North Korea filed a police complaint. The investigation was opened because the employee was treated for minor injuries, and her cries for help had alerted neighbors who summoned the police, officials said.

El Confidencial, a Spanish news site, said the woman told the Spanish police that a group of assailants had stolen computers and detained staff members. Police officers rang the doorbell of the embassy, but were told by an official that nothing unusual had occurred, El Confidencial reported.

In 2017, Spain expelled the North Korean ambassador in retaliation for North Korea’s missile testing. The ambassador, Kim Hyok-chol, played a leading part in organizing this week’s meeting in Vietnam between President Trump and the North Korean leader, Kim Jong-un.