A Chinese activist investigating a company that manufactures shoes for Ivanka Trump's label and other Western brands has been detained by police in China, and two of his colleagues remain unaccounted for.
The three activists were investigating labour conditions at Huajian shoe factories for China Labour Watch (CLW), a New York - based non - profit organisation that aims to defend workers' rights.
It lost contact with them last week, CNN reported on Wednesday.
The news came amid a broader crackdown in China on independent groups pushing for better labour rights in the world's second - largest economy.
One of the activists, Hua Haifeng, was detained by local police in Jiangxi province for "illegal surveillance, " said Li Qiang, the head of China Labour Watch.
The other two activists, Li Zhao and Su Heng, were missing, he said.
The activists took jobs between March and May at two factories run by the Huajian Group - - one in Jiangxi and the other in Guangdong - - in order to investigate labour practices at the company, Li said.
Su, who was working at the factory in Jiangxi, found evidence of violations of workers' rights during the production of Ivanka Trump shoes, CNN quoted Li as saying.
They included employees working for as many as 18 hours a day for pay below the minimum wage, he said.
Huajian didn't immediately respond to a request for comment.
A spokeswoman for Ivanka Trump's company also declined to comment.
A spokeswoman for Marc Fisher Footwear, which manufactures Ivanka Trump shoes, said the firm was unaware of the allegations and would look into them immediately.
Two other shoe brands under the company's umbrella - - Marc Fisher and Kylie + Kendall - - were also being made at the Huajian factories, according to China Labour Watch.
Li said he was sending video footage shot by Su at the Jiangxi factory to Ivanka Trump's company.
"We appeal to President Trump, Ivanka Trump herself, and to her related brand company to advocate and press for the release of our activists, " he said.
Hua's wife, Deng Guilian, told CNN that she received a call Tuesday from police in Jiangxi telling her that her husband has been detained for conducting illegal surveillance and that she should expect to receive a formal notice in the mail soon.
The families of Li and Su couldn't be reached for comment.
Officials at the local police department in Jiangxi said they weren't aware of any cases involving China Labor Watch activists.