China has arrested a labor activist who was in the country investigating conditions at the plant that makes the shoes for the clothing line belonging to Ivanka Trump, daughter of Donald Trump.  Two other activists are missing.

"We appeal to President Trump, Ivanka Trump herself, and to her related brand company to advocate and press for the release our activists," read the statement from the New York-based China Labor Watch, which was planning on publishing a report "alleging low pay, excessive overtime and the possible misuse of student interns".

Police called labor activist Hua Haifeng's wife to say he was under arrested and accused of "illegal surveillance" and that "she would not be able to see, speak with or receive money from her husband".  The two other men, Li Zhao and Su Heng are missing.

They had uncovered evidence of workers putting in excessive overtime at the Ganzhou Huajian International Shoe City Company's factory in Jiangxi province, with working days sometimes stretching longer than 18 hours, and a base salary below minimum wage.  They also say the company abused student interns.

The Ivanka Trump brand supposedly produces 20 million pairs of shoes annually, and Huajian provides 10,000 to 20,000 every year.

The Democratic National Committee (DNC) says the Trump family needs to "confront China on its human rights abuses".

"We deeply hope that these detained or missing human rights workers are safe and can be reunited with their families as soon as possible," said DNC deputy communications director Adrienne Watson.  For years, Ivanka Trump has ignored public reports of awful labor conditions at a factory that makes her shoes.  Now, she must decide whether she can ignore the Chinese government's apparent attempt to silence an investigation into those worker abuses."