A "full scale" terror attack drill will take place on Wednesday in the US capital of Washington DC.

The drill will occur across six sites in DC, Northern Virginia and Maryland and will include hundreds of volunteer actors, emergency medical personnel, police and fire officials.

The Metropolitan Washington Council of Governments announced the exercise in a press release on Tuesday.

The drill will run from 7.30am until 8.30am.

The locations include neighbourhoods in the northeast and southeast quadrants of the District of Columbia, Prince George's County, and Arlington and Fairfax Counties.

Residents in those neighbourhoods have been informed, so as not to be alarmed at the sight of the exercise.

"Law enforcement officials practice and exercise their skills on their own regularly because that's the best way to ensure we are always ready to respond quickly and professionally," said Scott Boggs, Managing Director of Homeland Security and Public Safety at COG.

"On April 26, we'll go one step further and stage a very realistic emergency event involving multiple sites and actors posing as the casualties. However, there is no reason for residents to be alarmed because the exercise will occur in a controlled environment."