Police hunt gunman on Capitol Hill

Armed police tonight chased a gunman through a building in the heart of Capitol Hill in Washington before he managed to escape south of the Capitol.

He is armed with a .38 calibre handgun, according to reports.

Security guards spotted a handgun in the man’s backpack as he passed through a metal detector.

But before they could challenge him, he ran inside the Cannon House Office building, Congress officials confirmed.

Parts of Capitol Hill were evacuated while armed police searched room by room for the man.

The building houses between 80 and 100 Congressmen, who have been moved out.

The operation to find the man was being led by the Capitol Hill police service.

The 671,921 sq ft Cannon House Office Building was completed in 1908 and is the oldest congressional office building.

Tunnels linking various Capitol Hill buildings have been sealed.