A man who claimed that he was armed was taken into custody Tuesday evening at a shopping mall in Montgomery County, authorities said.

Police determined that the man was carrying no weapons, but the timing of the incident at Westfield Montgomery Mall provoked concern. It came days after three people were shot and killed Saturday at a mall in neighboring Howard County.

In addition, the incident came on a night of special security precautions for the President Obama’s State of the Union address.

The man involved showed signs of mental instability, said a state police supervisor, and as a crowd gathered in the mall to watch, he was taken into custody for mental evaluation.

An employee of a mall store who saw the man while police questioned him said he seemed distraught, as he stood and looked down while holding a hand on his forehead.

The man, who appeared to be in his early 20s, wore camouflage pants, or overalls, of the kind worn by hunters, the witness said. He “just looked really upset,” the witness said.

The employee asked not to be identified because the business she worked for did not authorize her to speak. She said the police appeared to be unruffled in their response.

“They seemed pretty calm,” she said. “They knew what they were doing.”

After talking to the man, she said, they placed him in handcuffs and led him onto an escalator.

Nonetheless, the employee said, “I was a little scared.”

In the wake of reports of Saturday’s incident at the Mall in Columbia, she said, a mall shooting “is like my biggest fear.”

Cpl. Rick Luzier of the state police Rockville barracks said Montgomery County police were called about 6:15 p.m. to the mall on Democracy Boulevard in the north Bethesda area. The report was for a man who was acting suspiciously at the shopping mall, a two-level structure that includes a food court and dozens of retail stores.

The man had made “miscellaneous threats” to employees at the mall, including the suggestion that he might have had a gun with him, Luzier said.

Officers from the county and state police arrived. Luzier said the state police sent four officers. The witness said she saw as many as six county officers.

Officers “made contact” with the man and determined that he carried no weapons, Luzier said. The state police took jurisdiction in the matter.

The mall was not evacuated, Luzier said.

The man taken into custody was not identified and there was no report of any charges.

Employees of at least two restaurants at the mall said they had neither seen or heard anything out of the ordinary.

One, puzzled by a reporter’s questions, finally asked him if he wished to place an order.