Pittsburgh Siege: Man surrenders to police after hostage situation unfolds over Facebook

Police block off the area around Three Gateway Center building during the hostage situation (AP)

An armed man holding a hostage inside a high-rise building in Pittsburgh has surrendered to police.

The hostage is said to be unharmed following a standoff where the man, identified by police as Klein Michael Thaxton, posted live updates to his Facebook profile.

Initially claiming to have a gun and a bomb, 22-year-old Thaxton walked into an office on the 16th floor of the Three Gateway Center building shortly after 8am local time and took a hostage.

Making his Facebook profile visible to the public, he began posting messages mid-morning, claiming he was tired of life while strangers responded with prayers. Some friends however encouraged him to continue his stand-off, and police warned criminal charges could be brought against anyone considered to be an accessory.

Posting what he claimed was his telephone number, Thaxton wrote: “I can’t take it no more.”

In another message he said: “This life im livn rite now i dnt want anymore ive lost everything and i aint getting it back.”

Police Chief Nate Harper described Thaxton as “ex-military” and said he had been cooperative throughout the negotiations.

Thaxton is not thought to have had links with the office, which handles union pensions.