China-based hackers breached the email account of US Ambassador to China Nicholas Burns as part of a recent targeted intelligence-gathering campaign, three US officials familiar with the matter told CNN.

The hackers also accessed the email account of Daniel Kritenbrink, the assistant secretary of State for East Asia, who recently traveled with Secretary of State Antony Blinken to China, the people said.

CNN has requested comment from the State Department.

The news, first reported by the Wall Street Journal, adds to the fallout for the US of the alleged Chinese hack first revealed last week. The hackers also infiltrated the emails of Commerce Secretary Gina Raimondo, CNN previously reported.

This story is breaking and will be updated.