The use of social media apps to sell domestic workers illegally is on the rise in Middle Eastern countries, according to a new investigation by the BBC.

The BBC Arabic undercover team recently revealed an online black market for modern slavery in Kuwait and Saudi Arabia. The team discovered hashtags and private messages on Instagram and Facebook that facilitated the sales of domestic workers to help with chores around the house like cleaning and caretaking. Apps available on Google Play and Apple’s app store promoted ads for illegal labor. 

Anti-slavery advocates say the major tech companies must be held accountable.

"What they are doing is promoting an online slave market," Urmila Bhoola, the UN special rapporteur on contemporary forms of slavery said, according to the BBC.

On the e-commerce website and app 4Sale, women were categorized by race and available to buy for a few thousand dollars.

"African worker, clean, and smiley," one listing said.

The BBC Arabic undercover team spoke to 57 4Sale users and visited more than a dozen people who had advertised domestic labor. 

"You will find someone buying a maid for 600 KD ($2,000), and selling her on for 1,000 KD ($3,300)," one policeman, who was trying to sell his worker, told the team.

Almost all of the sellers mentioned carrying out human rights abuses against their workers. The sellers threatened to confiscate the workers’ passports, not let them leave the house, give them no time off or deny them access to a phone. 

The BBC also found that hundreds of women were being sold on the Saudi Arabia-based e-commerce website and app Haraj and on Instagram. 

Domestic workers are common in Kuwait — as many as 9 out of 10 homes in the country employ then. Workers often go to Kuwait in search of an opportunity to support their families back home. Under the Kafala system to monitor migrant laborers, domestic workers cannot change their job or leave the country without their sponsor’s permission. 

Kuwait passed some laws to protect domestic workers in 2015, but people still find loopholes.

Potential employers pay agencies a fee and become the official sponsor of a worker through the government. Online employers have found ways to sell the sponsorship of their domestic worker to other employers, allowing buyers to bypass the agencies, making it easier to exploit vulnerable women. 

Some 45 million people are trapped in modern slavery around the world. Globally, an estimated 71% of enslaved people are women and girls, while men and boys account for 29%. Women and girls who are trafficked face high rates of physical and sexual violence, as well as mental and physical health issues. Children who have been trafficked often end up missing out on their education and get stuck in a cycle of poverty and slavery. 

The apps fostering human trafficking are taking some steps to address the issue, but hundreds of workers continue to be traded online, according to the BBC.

Since the BBC contacted 4Sale about the activity taking place on the app, the company has removed its domestic worker section. Haraj did not respond to the BBC’s request for comment.

“We will continue to work with law enforcement, expert organizations and industry to prevent this behavior on our platforms," a Facebook spokesman said. 

The Arabic hashtag #maidsfortransfer, which was being used to sell workers, is now banned on Facebook.

Google and Apple also said they are working with developers to prevent illegal activity. Despite their statement, related listings are still active on Instagram and other apps available on Apple and Google, the BBC found. 

The Kuwaiti government said it’s trying to stop this behavior and will investigate all of the apps. No significant action has been taken yet against the platforms, according to the BBC. 

Countries need to push for policies that prevent slavery, the organization Anti-Slavery International says. Investing in research that brings modern slavery to light will else help stop these human rights abuses and forms of exploitation.