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.