BOSTON — A Turkish national who is a doctoral student at Tufts University has been detained by federal agents without explanation, her lawyer said Wednesday.

Rumeysa Ozturk, 30, had just left her home in Somerville to meet with friends Tuesday night when she was detained by U.S. Department of Homeland Security agents, lawyer Mahsa Khanbabai said in a petition filed in Boston federal court.

Video obtained by The Associated Press appears to show six people, their faces covered, taking away Ozturk’s phone as she yelled and was handcuffed.

“We’re the police,” members of the group are heard saying in the video.

Khanbabai said Ozturk, who is Muslim, was meeting friends for iftar, a meal that breaks a fast at sunset during Ramadan. “We are unaware of her whereabouts and have not been able to contact her. No charges have been filed against Rumeysa to date that we are aware of,” Khanbabai said in a statement. Ozturk has a visa allowing her to study in the United States, Khanbabai said.

Massachusetts Attorney General Andrea Joy Campbell called the footage “disturbing.”

— The Associated Press