A soldier stationed in Colombia (search) as part of the U.S. war on drugs pleaded guilty Thursday to participating in a scheme to smuggle cocaine into the United States using military planes.

Army Staff Sgt. Kelvin Irizarry-Melendez (search) pleaded guilty to conspiracy, wrongful importation of cocaine and a charge related to taking money to Colombia.

The judge, Lt. Col. Jeffery Nance, accepted the plea, and a sentencing hearing was scheduled for Thursday afternoon.

Irizarry-Melendez and three other soldiers were accused of smuggling cocaine (search) from a U.S. base in Colombia. All four have been jailed since their arrests earlier this year.

Irizarry-Melendez also was accused of making a false official statement and illegal use of cocaine, according to post officials. The status of those charges was unclear Thursday.

Accused ringleader Staff Sgt. Daniel Rosas, who is scheduled to stand trial later this month, told investigators that he and Irizarry-Melendez were responsible for the drug smuggling, with the other two soldiers concentrating mostly on fronting money to buy the drugs.

Irizarry-Melendez told the judge Thursday that he assisted the operation but didn't smuggle drugs or money.

Spec. Francisco Rosa pleaded guilty last month to a series of charges and was sentenced to five years in prison, a reduction in rank to private and a bad-conduct discharge.

Staff Sgt. Victor J. Portales is scheduled for trial in November.