Hackers operating from an elite Chinese university probed American companies and government departments for espionage opportunities following a U.S. trade delegation visit to China earlier this year, security researchers told Reuters.

Cybersecurity firm Recorded Future said the group used computers at China's Tsinghua University to target U.S. energy and communications companies, as well as the Alaskan state government, in the weeks before and after Alaska's trade mission to China. Led by Gov. Bill Walker, representatives of companies and economic development agencies spent a week in China in May.

Organizations involved in the trade mission were subject to focused attention from Chinese hackers, underscoring the tensions around an escalating tit-for-tat trade war between Washington and Beijing.