A federal appeals court has thrown out the 17-year prison sentence imposed on convicted terrorism plotter Jose Padilla.

A three-judge panel of the 11th U.S. Circuit Court of Appeals ruled Monday that the sentence imposed by a Miami federal judge was too lenient. The appeals court sent the case back for a new sentencing hearing.

Padilla and two co-conspirators were convicted in 2007 after a three-month trial in which prosecutors said they sent money, recruits and supplies to Islamic extremist groups including al-Qaida. The appeals ruling upheld all the convictions.

Padilla was arrested in 2002 at Chicago's O'Hare International Airport on suspicion of plotting to set off a radioactive "dirty bomb." He was held for 3 1/2 years as an enemy combatant without a criminal charge.