A federal jury has convicted a retired University of Tennessee professor of passing secrets from a U.S. Air Force contract to two research assistants from China and Iran.

Jurors deliberated about six hours before finding plasma physics expert J. Reece Roth guilty Wednesday on 18 counts of conspiracy, fraud and violating the Arms Export Control Act.

Prosecutors in the Knoxville trial said Roth gave two graduate students access to sensitive information while they researched a plasma-guidance system for unmanned aircraft.

The 70-year-old Roth testified last week that he didn't break the law.

He faces up to 160 years in prison and more than $1.5 million in fines. Sentencing is scheduled for Jan. 7.