A federal appeals court in California has overturned the prison term for the so-called “Millennium Bomber,” calling his 22-year sentence too lenient.

In an opinion released with the 9th Circuit Court of Appeal's decision Monday, Judge Richard Clifton said the lower court that sentenced Ahmed Ressam “committed a clear error of judgment.” He said the sentence was “substantively unreasonable.”

Ressam was arrested in 1999 as he tried to cross from Canada into the United States with powerful explosives in his vehicle.

He was convicted of nine counts in connection with a plot to bomb the Los Angeles International Airport on December 31, 1999. Prosecutors say he had trained in terrorist camps in Afghanistan.

The federal government argued that sentencing guidelines called for 65 years to life. A lower court will resentence Ressam.