A man pulled a gun during a legal proceeding Thursday and took as many as nine people hostage in an office in a central Phoenix high-rise, authorities said.

Police Sgt. Andy Hill said the gunman and hostages were inside a hearing room in a National Labor Relations Board office on the building's 18th floor. The floors immediately above and below were evacuated.

"We are not aware that anyone has been hurt or that any shots have been fired," Hill said.

He said police had been in contact with the gunman, and had also contacted members of the hostage-taker's family and relatives of some of the hostages. Hill said the gunman had also been in touch with members of his family, though he didn't say how.

It was not immediately clear if the man was a participant in the proceeding — which an NLRB official called a "litigated trial" — or a bystander.

Cornele Overstreet, an NLRB regional director, told the local Fox TV affiliate that the gunman first "shouted out something" and grabbed a secretary as she was coming out of a bathroom.

Sioux Jeffrey, who works in another office on the same floor, said a man from the labor office came to her workplace "and told us to evacuate. 'There's a man with a gun."'

Everyone quietly left and walked down the stairs, she said.