Intel has tested chipmaking equipment this year from ACM Research, a firm with deep ties to China whose two overseas units were recently targeted by U.S. sanctions, according to two sources with direct knowledge of the matter.

The U.S. chipmaker, which in August faced calls from President Donald Trump for its CEO to resign over alleged links to China, obtained the tools from ACM Research, a Fremont, California-based manufacturer of semiconductor equipment.

ACM’s Shanghai and South Korea units were among several firms barred last year from receiving U.S. technology over allegations they supported China’s efforts to use commercial technology for military applications and to develop advanced chips or chipmaking tools. ACM denies the accusations.