WASHINGTON — Attorney General William Barr waded into ongoing diplomatic tensions between the United States and China today, decrying what he said was Beijing’s determination to establish “dominance” in the market of next-generation, high-speed wireless networks.

Barr spoke as the Trump administration has accelerated efforts to warn other countries to be wary of Chinese investment and influence. The U.S. government has been lobbying allies to ban Chinese tech giant Huawei from involvement in the network because of cybersecurity concerns.

Barr’s comments came at a conference for FBI and Justice Department officials centered on concerns about Chinese economic espionage and intellectual property theft.

The number of FBI arrests in cases related to Chinese espionage has risen sharply in the last five years, corresponding with what the U.S. government sees as an urgent threat to American economic prosperity and intellectual property, federal law enforcement officials said.

There were 24 China-related arrests in the last fiscal year, up from 15 five years earlier, and there have been 19 this year, according to Justice Department figures presented Thursday,

Officials described urgent law enforcement and intelligence efforts to counter China’s targeting of corporate trade secrets and academic research, including defense information, software for wind turbines and high-end medical technology. In recent years, U.S. officials say, China has relied not only on hacking to steal information but also on recruitment of scientists and other individuals.

“The long-term existential threat to the security of our nation is real,” said Bill Evanina, the U.S. government’s top counterintelligence official.

An email sent to the Chinese Embassy seeking comment was not immediately returned today.

The U.S. officials highlighted a series of prosecutions over the last year that they say underscore the threat, including the recent arrest of a hospital researcher in Boston accused of attempting to smuggle biological material from a laboratory to China.