LOS ANGELES – An Uzbek refugee serving 25 years in prison for plotting to help a foreign terrorist group has been sentenced to another 20 years for trying to kill a federal prison warden in California.

Fazliddin Kurbanov was sentenced Monday in Los Angeles. Prosecutors say he acknowledged fashioning a knife and trying to slit the warden’s throat at a federal prison in Victorville.

Calvin Johnson, the warden, recovered from the 2016 attack.

Kurbanov pleaded guilty in March to attempted murder of a federal officer.

Kurbanov’s new sentence will run consecutively with his current sentence for trying to provide material support to the Islamic Movement of Uzbekistan, a terrorist group.

Authorities say that before his 2013 arrest, Kurbanov bought bomb-making materials and plotted to kill U.S. military personnel or civilians at Fourth of July celebrations.