DUBAI — The advent of Instagram in recent years has helped create an international black market for migrant workers, in particular women recruited in Africa and Asia who are sold into servitude as maids in Persian Gulf countries.

Unlicensed agents have exploited the social media platform to place these women into jobs that often lack documentation or assurances of proper pay and working conditions. Several women who were marketed via Instagram described being treated essentially as captives and forced to work grueling hours for far less money than they had been promised.

“They advertise us on social media, then the employer picks. Then we are delivered to their house. We are not told anything about the employers. You’re just told to take your stuff, and a driver takes you there,” said Vivian, 24, from Kenya.

When she landed in Dubai last fall on a flight from Nairobi, Vivian said she had expected to begin work immediately as a maid, but instead her recruitment agent drove her to a house on the outskirts of the city and locked her in a cramped room with 15 other women. She was held there for several weeks, sleeping on the floor, until the agent found her an employer by advertising on Instagram, she said. Her photo had been uploaded onto her agent’s account, which was examined by The Washington Post, along with personal details such as her weight, nationality and date of birth.

A review of Instagram activity by The Post identified more than 200 accounts that appeared to play a role in marketing women as maids in countries including Kuwait, Saudi Arabia and the United Arab Emirates.

Such black-market networks have sprung up alongside legal recruitment networks that over the years have placed millions of women into jobs as domestic servants in the Persian Gulf region. Although women who are recruited and placed through a licensed agency can also face a difficult work environment, they are afforded better workplace protections and, because they are documented, have more recourse if they’re abused and can seek help from their embassies, according to labor experts.

“Migrant workers who are recruited through more informal channels, including by unlicensed agents, are at higher risks of trafficking and other forms of exploitation,” said Rothna Begum, senior women’s rights researcher at Human Rights Watch.

Fabien Goa, research manager at the FairSquare Projects, a British-based human rights group, said that “deception with intent to abuse people by putting them in employment they haven’t actually agreed to has all the hallmarks of trafficking.”

In response to a request for comment last month, an Instagram spokesperson asked for the list of accounts identified by The Post so company officials could investigate. Instagram has since deleted these accounts.

“Human exploitation is horrific, and we don’t allow it on Instagram. We’ve disabled all the accounts reported to us,” said Stephanie Otway, a spokeswoman for Facebook, which owns Instagram. It is unclear whether other similar accounts remain on the platform and, if so, how many.

Asked why Instagram had not identified these accounts on its own, Otway said: “We’ve developed technology to detect this kind of content and behavior, but it’s not perfect. We’re constantly working to improve this technology to help us catch more of this content more quickly.”

She said that Instagram was already taking this kind of activity “extremely seriously” and that it has been consulting with expert organizations to target various forms of human exploitation and trafficking that use the social media platform.

Some of the accounts identified by The Post belonged to people based in the women’s countries of origin, such as Ethiopia and Kenya, with the account owners advertising the women to recruiters in the Middle East. Other accounts belonged to agents in the Middle East and were used to advertise the women to individual households.

Ryszard Cholewinski, the senior migration specialist at the U.N. International Labor Organization, said these women are being subjected to “forced labor.” He said, “If they disappear into the informal labor market and end up in households, they effectively become invisible.”

Many of the Instagram posts gave the women’s full names and passport numbers, which could pose a privacy risk for them but also made it possible for eight maids to be located and interviewed for this article.

Vivian said she had been made to work from 5 a.m. until midnight, with no days off. (She spoke on the condition that her last name not be published out of concern that the agent would retaliate against her.) She was paid $272 per month, about $140 less than she said the recruiters promised her. She said she became ill and was still not allowed to rest.

After three weeks, she refused to go on working, and her employers requested a refund from her UAE agent for the $2,180 they had paid for her, Vivian recalled. The agent refused until they threatened to call the police.

“My agent was angry and told me he would take me to a place where I would regret forever. I was threatened,” she said.

She ran away and is still living in the UAE as an undocumented immigrant.

Vivian said she originally had been recruited in Kenya by a woman named Susan and, when shown a picture, confirmed that it had been Susan Wanjiku, director of the Alphasher Agency in Nairobi.

In an interview, Wanjiku said she recruited women as maids for licensed and unlicensed agents in Persian Gulf countries, using Instagram to connect with them. She denied that the women she recruits are abused or exploited. “This is a fake rumor that maids are mistreated and beaten. There is a contract, and that can’t happen,” Wanjiku said, referring to the written agreements domestic servants are supposed to have with their employers. “My maids go to good homes.”

The UAE agents are responsible for paying for the flight and visa fees, Wanjiku said. To ensure that these agents do not cheat her out of payment, Wanjiku never puts large groups of women on the same flight. “We ask for five visas to be paid by the agent in UAE, then I send each housemaid one day apart. So, before I release the second maid, they pay for the one that arrived. If I don’t get paid, I don’t release the other four maids with visa,” she said.

Vivian said in her case, she received a tourist visa and not a work residency visa, which is routinely provided by formal recruitment agencies. She said she was not given a contract, contradicting Wanjiku.

The Alphasher Agency charges the UAE agents $500 per woman, Wanjiku said. But migrants can command an even higher price, according to agents in Africa and the UAE. The owner of another recruitment firm in Ethiopia, which also markets maids via Instagram, said he gets $1,000 per woman from agents in the gulf countries.

Margarita Abad, 33, a widow from the Philippines, recounted that her agent in the UAE was paid $3,500 for placing her in a household.

At the time, Abad did not know she was marketed over Instagram until she was told by a reporter. “I didn’t give permission. I feel bad about it. It’s like they sold me in an auction,” she said.

Abad traveled to the UAE about two years ago, hoping to find a good job that could help her provide for her two young children back home. Instead, she said, she was placed with an abusive employer.

She recalled that her employer would often refuse to feed her. “There were times when I cried while I was eating because I was so hungry,” she said. She lost 40 pounds.

“Once the agency has sold a maid, they don’t care anymore,” Abad said. “They just want the money.”