A small aircraft is believed to have struck Beijing’s tallest skyscraper on Friday, prompting a large emergency response after witnesses reported seeing wreckage at the base of the building.

The incident involved the 528-metre CITIC Tower in the Chinese capital, where eyewitnesses and journalists observed damage to windows on one of the upper floors. Emergency crews, including firefighters, police officers and ambulances, quickly arrived at the scene as authorities restricted access to the area.

Videos recorded from nearby buildings showed firefighters working to extinguish small fires close to the building while what appeared to be aircraft debris lay on the ground. Another clip circulating online seemed to show pieces of debris falling from the tower, although the footage could not be independently verified.

Witnesses expressed surprise that an aircraft could enter such a heavily controlled section of Beijing’s airspace. One office worker described the incident as unusual, while another person leaving the building said the debris looked like parts of a plane.

Employees inside the skyscraper said they were instructed to leave the building using the stairwells instead of elevators. One worker recalled rushing down dozens of floors during the evacuation.

The area remained under tight security as police blocked members of the public from approaching the scene or taking photographs. Officials did not immediately provide details about the cause of the incident or whether there were casualties.

The 108-storey CITIC Tower is one of Beijing’s most prominent office buildings and can accommodate around 12,000 workers.

China maintains strict controls over its airspace, particularly in and around Beijing. Earlier this year, authorities introduced tighter regulations on drone operations in the capital, requiring official approval for all drone flights, while separate restrictions were also imposed on parts of the country’s civil aviation airspace.