Hostage taken at Discovery HQ in US

An Asian man who police believe may have explosives strapped to his body has taken at least one hostage in the Discovery Channel headquarters building in suburban Washington.

Police sealed off the area around the building and SWAT teams were at the scene. The incident began on Wednesday afternoon. The building was evacuated and children were removed from a day-care centre.

"He appears to have some sort of explosive device on his person," Captain Paul Starks told reporters. He said the police were in contact with the suspect, who had made some demands that authorities would not reveal.

"I don't know anything about his history," Mr Starks said when asked by reporters about any possible relationship the gunman may have with Discovery.

Local media reported that police said the man's name was James J Lee. A man named James Lee of San Diego was arrested in February 2008 after throwing money into the air in a protest outside the Discovery building, a local newspaper reported that year.

Montgomery County Police Corporal Dan Friz said of the suspect: "His concerns are with the Discovery Corporation right now." He would not go into further details.

"There may be some other potential devices with him, or near him that he brought in, but again none of this has been confirmed," he said to reporters.

Mr Friz said he could not confirm that gunshots were fired in the building as a Discovery employee had told television news earlier.