U.S. efforts to prosecute Chinese nationals for criminal activity, such as the current effort to extradite a Huawei Technologies Co. executive who was arrested in Canada, are based on years of investigative activity and not politics, a top U.S. Justice Department official said.

“Law enforcement is what we do at the Justice Department," John Demers, head of the department’s National Security Division, said in an interview Tuesday on Bloomberg Television. “We follow those facts to see if there are violations of U.S. law."

Huawei Chief Financial Officer Meng Wanzhou, the daughter of the technology company’s founder, was arrested in Canada this month at the request of the Justice Department, which wants to extradite her to the U.S. to face criminal charges for alleged dealings with Iran. The U.S. has warned Beijing could employ Huawei’s networks for espionage, something the provider of telecommunications and networking equipment has always denied.

Demers said such cases are “based on years’ worth of investigation” and are “not something we thought of in the last year or so.”

President Donald Trump has suggested he might intervene in the case as part of his efforts to boost a China trade deal, raising concern that independent law enforcement operations might be used as bargaining chips.

Demers said extradition requests aren’t matters that he and his team talk to the White House about. He declined to comment specifically on the case of Meng, or on efforts by Turkey to have the U.S. extradite cleric Fethullah Gulen.

China has taken a “rob, replicate and replace approach to economic development” in stealing intellectual property from companies in the U.S. and other countries, Demers said. He said the U.S. has been “very patient” waiting to see if China would change its approach, but so far it hasn’t.

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