Chinese and U.S. envoys sparred at the World Trade Organization on Monday over U.S. President Donald Trump's claims that China steals American ideas, the subject of two lawsuits and a White House plan to slap huge punitive tariffs on Chinese goods.

U.S. Ambassador Dennis Shea said "forced technology transfer" is often an unwritten rule for companies trying to access China's burgeoning marketplace, especially if they are partnering with a state-owned or state-directed Chinese firm.

China's licensing and administrative rules force foreign firms to share technology if they want to do business, while government officials can exploit vague investment rules to impose technology transfer requirements, he said.