[Updated at 1:59 p.m.] The man suspected of taking a hostage in Pittsburgh's Gateway Center high-rise Friday morning has surrendered peacefully, and his hostage was not harmed, Pittsburgh Police Chief Nathan Harper said.

[Updated at 1:20 p.m.]Police are negotiating with a "relatively calm" gunman believed to be holding at least one person hostage in a downtown Pittsburgh high-rise, the city's police chief said Friday.

Police have identified the man, a former military member with a criminal record, and they brought his mother to the scene, Chief Nathan Harper said.

The suspect walked into CW Breitsman Associates' office Friday morning and asked for a particular man, so police believe a male hostage was targeted, Harper said. CW Breitsman handles money for pension funds. The chief said the gunman never worked there, and it's unclear how he was related to the company.

The situation is contained to one room of a suite on the 16th floor of Gateway Center Building No. 3, Harper said. As of 10:55 a.m., no one had been hurt and no shots had been fired, he added.

Police received calls shortly after 8:15 a.m., reporting a man with a gun. Some witnesses reported he was carrying two duffel bags. Harper said the suspect also claimed to have a bomb.

Several people who work in the building told local television stations that police had evacuated them from the building. Harper said since the incident was contained to one room, evacuations were minimal, and people were still occupying other parts of the skyscraper.

Jim Garra, who works at AXA on the 16th floor, told WTAE that when he arrived at work around 8:10 a.m., security officers were milling about. When he took the elevator to his office, he found a commotion, including a woman he described as "hysterical, on the phone," describing an intruder in the building. Garra said he locked the door to his office until police came to evacuate it.

Public transportation has been shut down at Gateway Center, and police have blocked off nearby roads as well.