Suspected Chinese hackers have broken into the email accounts of attorneys and advisers at a powerful Washington, DC, law firm in an apparent intelligence-gathering operation, the firm, Wiley Rein, told clients this week in a memo reviewed by CNN.

The hackers responsible have been known to target information related to trade, Taiwan and US government agencies involved in setting tariffs and reviewing foreign investment, said the notice from the firm.

“We believe, based on the evidence reviewed to date, that a group that may be affiliated with the Chinese government accessed messages in the Microsoft 365 accounts of certain Wiley personnel for intelligence gathering purposes,” the memo said.

The breach comes after the Trump administration escalated America’s trade war with China this spring by slapping unprecedented tariffs on Chinese exports to the United States. The tit-for-tat tariffs set off a scramble in both governments to understand each other’s positions.

With clients that span the Fortune 500 and a team of top trade attorneys, Wiley Rein is a powerful player in helping US companies and the government navigate the trade war with China. The firm describes itself as “wired into Washington” and says it provides “unmatched insights into the evolving priorities of agencies, regulators, and lawmakers.”