At least one shot at US Navy base in Washington
A gunman has shot at least one person at the Washington Navy Yard, a naval installation in the US capital, say officials.
The US Navy confirmed police had entered the building in search of a gunman, after at least three shots were fired at 08:20 local time (13:20 GMT).
At least one person was injured, the Navy said.
Personnel at the base have been ordered to "shelter in place", the Navy said.
The US Navy said shots were reported to have been fired at the Naval Sea Systems Command headquarters at the yard in south-east Washington DC.
Dozens of emergency vehicles have converged on the site.
As many as 3,000 people work at the command, which engineers, purchases, builds and maintains ships and submarines for the Navy.
The Washington Navy Yard is the US Navy's oldest shore installation, first opened in the early 19th Century, according to the Navy.
Source: BBC News