WASHINGTON: A Somali man pleaded guilty Friday to taking part in an armed attack on a US warship off the Horn of Africa in April and will likely face 30 years in prison, the Department of Justice said.

Jama Idle Ibrahim appeared before a judge in Norfolk, Virginia, in relation to the April 10 attack in the Gulf of Aden of the USS Ashland, which he and five other Somali pirates mistook for a merchant ship. They were promptly captured after a brief skirmish.

Ibrahim pleaded guilty to piracy-related charges including "attack to plunder a vessel," "engaging in an act of violence against persons on a vessel" and "use of a firearms during a crime of violence."

Five other charges against Ibrahim, including taking part in an act of piracy, were dropped August 17 by judge Raymond Jackson after deciding prosecutors had failed to show the April attack constituted an act of piracy.

While Ibrahim could be sentenced from 10 to 30 years in prison for his crimes, a plea agreement settled for 30 years. Sentencing is scheduled for November 29.

The other five co-defendants in the case are still being prosecuted.

Five other Somalis arrested after the March 31 attack on the USS Nicholas off the Seychelles islands are also being prosecuted in another court on piracy charges.

BDST: 0957 HRS, August 28, 2010