An arrest by the F.B.I. comes as the Trump administration has promised to crack down on Chinese academics. The Justice Department announced charges on Tuesday against two Chinese researchers accused of trying to smuggle a fungus into the United States, bringing the case as the government pushes to keep more Chinese students out of the country.

Two Chinese nationals have been charged with allegedly smuggling into the U.S. a fungus called "Fusarium graminearum, which scientific literature classifies as a potential agroterrorism weapon," the Justice Department said Tuesday.