Alarm was raised shortly before 5pm Greek time outside the southern section of the White House after a man, who is reported to have been armed, drove his car into protective barriers. The man, who is reported to have been armed, was arrested.

protothema.gr correspondent Giannis Charamidis is at the scene, providing real-time coverage of the security response in the US capital. The White House was placed in lockdown, and journalists who were there were instructed to move inside the building.

Security services immediately established a cordon following reports that the man was armed.

Watch video of the security operation and what is happening at this hour in the heart of Washington: