BEIJING—Chinese police issued wanted notices for three people they said engaged in cyberattacks against China on behalf of the U.S. National Security Agency, a rare step by Beijing as hostilities between the superpowers escalate.

China alleges that the U.S. National Security Agency launched cyberattacks during the Asian Winter Games in February

China says it is pursuing three alleged U.S. operatives accused of carrying out cyberattacks on Chinese infrastructure during the Asian Winter Games.