Several floors in the Pentagon building have been placed on lockdown following the detection of an "air quality issue", prompting hazardous material (hazmat) response teams to the scene.

The building's systems detected an "air quality issue necessitating precautionary measures until we determine its significance," said Pentagon spokesperson Sean Parnell in a statement.

"The Department is executing standard protection protocols, including a shelter-in-place order for the affected area," Parnell said.

The Pentagon is being assisted by Arlington Fire & EMS, who posted on social media that they are responding to a hazardous materials incident.

Police in the building are wearing gas masks and full chemical protective gear, US media reported.

Just before 11:00 EST (16:00 GMT), the Pentagon Force Protection Agency sent an email to Pentagon personnel to shelter in place in four corridors from the second to the fifth floors, according to CBS News, the BBC's US news partner.

The email told staff to comply with the directive and move in-person meetings to virtual meetings, according to CBS News.

The Pentagon, located in northern Virginia just outside Washington DC, serves as the US Defence Department's headquarters, with more than 20,000 government employees working in the building.

The former CIA official has been charged with theft of public funds relating to timesheet claims he made.

Police say the bus failed to slow ahead of a work zone and struck six vehicles on the motorway.

The child fired a single shot at a teacher, who had to have surgery after the incident in 2023.

On the final day of the state visit, the royal couple headed to Virginia for a more informal experience of the US.

The court deemed the new map and the bill that triggered it unconstitutional, following a lawsuit from the Republican National Committee.