SEATTLE — President Xi Jinping pledged in a speech here on Tuesday night to work with the United States on fighting cybercrime, saying that the Chinese government was a staunch defender of cybersecurity.

“The Chinese government will not in whatever form engage in commercial theft, and hacking against government networks are crimes that must be punished in accordance with the law and relevant international treaties,” Mr. Xi said in an address to American business executives.

At the end of his first day of a state visit to the United States, Mr. Xi told his audience, which also included Chinese business leaders, that “China is ready to set up a high-level joint dialogue mechanism with the United States on fighting cybercrimes.”