A Cuban national has pleaded not guilty to charges he conspired to file 900 phony federal tax returns seeking $2.2 million in refunds by using employee information stolen from the University of Pittsburgh Medical Center.

Yoandy Perez Llanes (YAWN'-es) was indicted last summer but was extradited only last week from Venezuela. His attorney has agreed with prosecutors that the 32-year-old will remain jailed until trial.

Llanes and others are accused of taking phony tax refunds as Amazon.com credits, a service that Turbo Tax offers customers. Authorities say the credits were used to buy consumer electronics later sold online or kept by the conspirators.

Llanes was arraigned Friday in federal court in Pittsburgh.

His public defender has a blanket no-comment policy.