A Michigan woman was arrested by Secret Service officers after she was seen walking along the White House’s north fence with a handgun at about 8 p.m. Thursday, authorities said.

Secret Service plainclothes officers noticed a woman with a holster near Pennsylvania Avenue around the perimeter of the fence and notified uniform division officers, who then arrested her for having an unregistered 9 mm handgun in her holster, said Ed Donovan, the spokesman for the Secret Service.

The woman, whom authorities identified as April Lenhart, 23, was accompanied by another person, who was not arrested and had not been identified by the Secret Service late Thursday.

Donovan said Lenhart was not cooperating in her interview and that it was hard to know what her intentions were.

Lenhart was walking around the White House around the time of President Obama’s address to the nation inside the East Room. She was arrested just minutes after he concluded.

Her companion, a man, was checked, questioned extensively and released at the scene, according to Donovan.