GANZHOU, China — A worker with blood dripping from his head marked a low point in the tense, grinding life at a southeastern China factory used by Ivanka Trump and other fashion brands. An angry manager had hit him with the sharp end of a high-heeled shoe.

Workers from the factory, including one current and two former employees who spoke to The Associated Press, reported overtime that stretched past midnight, steep production quotas and crude verbal abuse at Ganzhou Huajian International Shoe City Co. They said beatings were not unheard of, but the shoe attack, which all three say they witnessed last year, was violent enough to stand out.

“He was bleeding right from the middle of the head,” the current worker said.

“There was a lot of blood. He went to the factory’s nurse station, passing by me,” said a second man, who said he quit his job at Huajian because of the long hours and low pay.

The three workers are the first people with direct knowledge of conditions at the Ganzhou factory to speak with the media. They spoke to the AP on condition of anonymity, for fear of retribution or arrest.

Last month, three men investigating conditions at the Huajian Group factory were detained, accused of illegally using secret recording devices to steal commercial secrets. They, like one of the three men AP spoke with, worked with China Labor Watch, a New York nonprofit that has been investigating Ivanka Trump’s Chinese suppliers for more than a year.

Li Qiang, founder of China Labor Watch, describes Huajian’s Ganzhou factory as among the worst he has seen in nearly two decades investigating labor abuses. His group says pay can be as low as a dollar an hour, in violation of China’s labor laws. According to China Labor Watch investigators, until recently, workers might get only two days off – or less – per month.

China Labor Watch said the company forced workers to sign fake pay stubs with inflated salary numbers and threatened to fire workers if they didn’t fill in questionnaires about working conditions with pre-approved answers. Workers also said the company pressured people not to speak with outsiders about conditions.

In comments to the AP, the Huajian Group declined to respond to specific questions, but broadly denied all allegations, calling them “completely not true to the facts, taken out of context, exaggerated.” The company said it operates lawfully and that China Labor Watch “invented so-called ‘facts’ by illegal means of buying undercover work, which has already affected the enterprise’s normal business seriously and affected the survival and employment of tens of thousands of staff.” The company noted its significant contribution to the economy and to society, particularly through its employment of disabled people.

Before taking on an official role as adviser to her father, Ivanka Trump stepped back from day-to-day management of her brand, but she has retained her ownership interest. She has not commented on the detentions or the reports of poor working conditions at one of her brand’s suppliers. Her spokeswoman declined to comment for this story.

Abigail Klem, president of the Ivanka Trump brand, said “the integrity of our supply chain is a top priority and we take all allegations very seriously.” The company says its products have not been made in the factory since March, but China Labor Watch said it had an April production schedule indicating that nearly 1,000 pairs of Ivanka Trump shoes were due in May.

In the past, some brands have used China Labor Watch’s reports as a tool to help keep their supply chains clean. Walt Disney Co., for example, investigated and ultimately decided to sever its relationship with at least one supplier following reports of poor conditions.

China Labor Watch outlined its findings in letters sent in June to Ivanka Trump at the White House and to other brands. So far, the group says it has gotten no response.

The group said it also sent Ivanka Trump a video taken inside the factory in May. That video included a clip in which a manager threatened to rough up a worker who had apparently arranged shoes in the wrong order.

“If I see them f—ing messed up again,” the manager yells, “I’ll beat you right here.”

The video has not been released to the public, but it was shown to AP at China Labor Watch’s office in New York.