A year ago, the US government introduced chip sanctions aimed at hobbling China's ability to develop advanced artificial intelligence. But those sanctions had loopholes that allowed Chinese firms to keep buying and building chips used to train some of the world's most advanced AI algorithms. Today, the US announced it is tightening controls to try to close those gaps. The new restrictions, announced by the Commerce Department, also impose new rules for reporting the sales of other types of advanced chips, new controls on sales of advanced chipmaking equipment and design software, and statutes to prevent Chinese companies from obtaining chips through foreign subsidiaries. "This is a doubling down by the Biden administration on the goals of last year's export controls," says Gregory Allen, who is director of a center for advanced studies at the Center for Strategic and International Studies and supports the restrictions.