WASHINGTON, DC (ABCNews.com) -- At least 12 people were killed and several injured in shooting rampage this morning inside the Navy Sea Systems Command headquarters building in Washington, DC, according to officials.
Among the dead was a gunman who was shot and killed.
Metropolitan Police Chief Cathy Lanier said authorities are searching for two additional men who are considered "potential" shooters. She declined to discuss what evidence led police to believe the massacre could have potentially been carried out by multiple shooters.
"We have reason to believe these people may be involved and we want to talk to them," Lanier said. She said there was "no known motive" for the massacre.
She said the other two men being sought were wearing military uniforms.