The sole surviving Somali pirate from the hostage-taking of commercial ship captain Richard Phillips was being flown to New York late Monday, hours after his mother appealed to President Obama for his release.

U.S. officials said Abduhl Wali-i-Musi was due to appear in federal court in New York and could arrive in the city late Monday night. The officials spoke on condition of anonymity because they were not authorized to discuss the case.

Investigators have determined that the suspect is at least 18 years old, one of the officials said. That means prosecutors will not have to take extra legal steps to put him on trial in a U.S. court.

Shortly after his capture, U.S. officials identified him as Abduhl Wali-i-Musi and said his age was between 16 years and 20 years of age. Later, Defense Secretary Robert Gates said all four of the pirates who held Phillips hostage for five days off the Somali coast were between ages 17 and 19. Gates did not address his name.

His mother insists he is only 16, and offered a different version of his name on Monday.

In a telephone interview with The Associated Press, Adar Abdirahman Hassan gave her son's name as Abdi Wali Abdulqadir Muse.

"I appeal to President Obama to pardon my teenager; I request him to release my son or at least allow me to see him and be with him during the trial," Hassan said from her home in Galka'yo town, 465 miles north of Somalia's capital.

Hassan said her son was coaxed into piracy by "gangsters with money."

Though no charges have been publicly filed yet, the suspect could face charges that carry a maximum sentence of life in prison.

Wal-i-Musi was taken aboard a U.S. Navy ship, the USS Bainbridge, shortly before Navy SEAL snipers killed the three remaining pirates holding Phillips hostage on a lifeboat launched from his cargo vessel, the Maersk Alabama.

The government had considered handing him over to authorities in Kenya, which has an international agreement to prosecute pirates.

Officials decided to send him to trial in New York in part because the FBI office there has a history of handling cases in Africa involving major crimes against Americans, such as the al-Qaida bombings of two U.S. embassies in East Africa in 1998.

Since the hostage standoff on the high seas ended more than a week ago, U.S. authorities have been examining details of the case, particularly Wal-i-Musi's age.

Rarely is someone younger than 18 put on trial in federal court, and to do so prosecutors must take a number of additional legal steps to assure the judge that the defendant belongs there and not in juvenile or state court.

Ron Kuby, a New York-based civil rights lawyer, said he has been in discussions about forming a legal team to represent the Somalian.

"I think in this particular case, there's a grave question as to whether America was in violation of principles of truce in warfare on the high seas," said Kuby. "This man seemed to come onto the Bainbridge under a flag of truce to negotiate. He was then captured. There is a question whether he is lawfully in American custody and serious questions as to whether he can be prosecuted because of his age."