Suspected Chinese hackers breached the personal and campaign email accounts of a Republican congressman who has been critical of the Chinese government, the lawmaker said in a social media post on Monday. 

Rep. Don Bacon of Nebraska is the first known lawmaker to have their email account hacked in an alleged Chinese espionage campaign. The hackers also breached the unclassified email accounts of senior State Department and Commerce Department officials, including the US ambassador to China and the Secretary of Commerce Gina Raimondo, in a cyberattack that was launched in May, CNN previously reported.

The hackers had access to Bacon’s personal and campaign emails for a month, according to Bacon’s post on X, the social media site formerly known as Twitter. Bacon sits on the House Armed Services and Agriculture committees, two issues of prime interest to Chinese policymakers.