Anti-human trafficking police raided two Phnom Penh brothels on Tuesday, freeing eight girls believed to be underage, officials said on Wednesday.

In one case, police descended on an unmarked tin shack at the base of Phnom Penh’s dilapidated White Building, where three women running the brothel were arrested and six girls, all believed to be younger than 18, were freed, said Eric Meldrum, director of investigations for Agape International Missions, an anti-trafficking group.

Three of the six girls were later confirmed to be underage, the youngest being either 13 or 14, he said.

Neighbors said that about 10 officers from the municipal anti-trafficking force raided the shack at about 7 p.m. The building is located near the entrance of a small alley that runs along the front of the crumbling White Building in Chamkar Mon district’s Tonle Bassac commune.

Khuort Sophal, 51, who sells fruit from a store in the alley, said the tin-shack brothel was well-known in the area.

“In the same way that people know I sell ‘madenh’ plums,” she said on Wednesday, “people knew what they were selling.”

Although the sex workers often bought fruit from her shop, Ms. Sophal said she had not suspected they were underage. She said they appeared to be about 20.

“I pity those ladies,” she said. “They looked very poor.”

Next door, 37-year-old Chhun Sreynath sat among the mirrors and old plastic mannequins of her hairdressing salon. She said she was glad that police shut down the business, with which her salon shares a wall.

“It’s a bad example for my daughter,” she said. “I don’t want her to see this sort of business.”

In a separate case on Tuesday, police made one arrest at the 7777 massage parlor in Chamkar Mon’s Tumnop Toek commune and freed three victims, two of whom were Vietnamese girls believed to be underage, said Phat Phalla, deputy chief of the municipal anti-human trafficking bureau.

Police raided the parlor at about 2:30 p.m. after a long investigation, Mr. Phalla said.

“I suspect that those two Vietnamese workers are under 18,” he said.

The brothel’s Vietnamese manager, Yor Thi Nga, 38, confessed to selling sex on the premises under questioning by police and will be sent to the Phnom Penh Municipal Court today, Mr. Phalla said, declining to comment further.

Mr. Meldrum of Agape said police had been proactive in shutting down suspected brothels in recent weeks, particularly in cases involving minors.

“If we can prove there were minors being sold, they will get shut down,” he said.

The girls rescued in Tuesday’s raids were put in the care of the Social Affairs Ministry, he added.