Near the end of his short trip to China, Elon Musk made a late Wednesday night stop at Tesla’s Shanghai Gigafactory to say a few words to his staff.

Tesla’s CEO had kind words for the hundred employees who stayed at the factory until midnight to greet him. “Thank you for being here late at night,” he said, according to a video posted on Tesla’s social media account. "It's been incredibly impressive how you have been able to overcome so many difficulties and so many challenges," he continued.

“It warms my heart," he said. “There’s so much positive energy.”

Musk’s midnight trip is the latest instance of the Tesla CEO praising the work ethic of his Shanghai employees. Tesla’s China factory is a key part of the company’s supply chain, producing over half of Tesla’s cars in 2022.

He praised his Chinese employees for “burning the 3:00 a.m. oil” last year in an interview with the Financial Times. Musk called the workforce “super-talented and hardworking” and that they “strongly believe in manufacturing.”

At the time, Tesla’s Shanghai factory was operating under a “closed-loop” system during the city’s two-month-long COVID lockdown. Workers lived and slept on-site to stop a COVID outbreak from disrupting production.

In April, employees in Shanghai complained that Tesla had slashed performance bonuses following a fatal accident at the factory a few months earlier. Frustrated employees took to Twitter, sending a flurry of messages to both Musk and his mother to complain about the decision. (Twitter is banned in China, but tech-savvy Chinese users can evade Beijing’s controls.)

The Tesla CEO responded on Twitter, saying he was “looking into” the complaints.

‘Laptop class’

Musk has been less effusive when talking about workers in the U.S. In his FT interview last year, he said American workers “are trying to avoid going to work at all.”

In June 2022, Musk revoked remote work privileges for Tesla’s corporate employees, demanding full-time in-person work, which he said was “less” than what was asked of factory workers. Musk also ended Twitter’s policy on working-from-home soon after taking over the social media company last October.

Musk has characterized his dislike for remote work as a matter of fairness.

“People should get off their goddamn moral high horse with the work-from-home bullshit,” he said in an interview with CNBC in May. He argued that professional workers, who he called the “laptop class”, were “asking everyone else to not work from home while they do.”

Other tech CEOs are also pushing back against remote work, though not as aggressively as Musk. Meta will make employees assigned to an office come in three days a week starting September, reports The Information. CEO Mark Zuckerberg earlier suggested that newly hired engineers were more effective with some level of in-person work compared to fully remote engineers.

Musk’s China trip

Musk left China on Thursday, ending a short trip that began on Tuesday. The Tesla CEO had several meetings with senior Chinese officials, including the country’s foreign and commerce ministers. Musk also met with the CEO of Contemporary Amperex Technology, the market leader in EV battery manufacturing.

He told Chinese officials that U.S. and Chinese interests were connected, and that Tesla wanted to expand further in the country, according to Chinese government statements.

This story was originally featured on Fortune.com