May 21 (Bloomberg) -- A Somali captured last month after U.S. Navy commandos freed an American cargo-ship captain held by pirates off the Horn of Africa pleaded not guilty to piracy charges at his arraignment in federal court in New York.

Abduwali Muse was charged May 19 by a federal grand jury on a 10-count indictment accusing him of crimes including piracy and violence against maritime navigation. He faces mandatory life imprisonment if convicted.

Muse appeared today in Manhattan federal court before U.S. District Judge Loretta Preska. After his capture, a federal judge ordered him detained and rejected a claim by his lawyers that Muse is 15 years old. The judge said the slender Somali, who stands 5 feet, 2 inches, will be treated as an adult.

“How do you plead sir?” Preska asked Muse today.

“Not guilty,” he answered through an interpreter.

Muse allegedly was among a group of pirates who overtook the Maersk Alabama on April 8 and held its captain captive for five days. The group subsequently kept the captain, Richard Phillips, 53, in a lifeboat off the Somali coast.

AK-47

Muse, who prosecutors say was armed with an AK-47 weapon, was apprehended by U.S. sailors and taken aboard the USS Bainbridge for treatment of his injured arm when Navy snipers shot dead the three kidnappers in the lifeboat, the military said.

Prosecutors said Muse was the leader of the pirate crew that seized the Alabama. He was the first pirate to board the ship, fired at the captain from the deck, forced Phillips to stop the ship, and demanded that he hand over $30,000 from the ship’s safe, according to court papers, which recount statements made by Phillips.

The indictment alleges Muse canvassed the ship with an unnamed crew member. While he was doing so, another crew member tackled Muse, and the two crew members subdued him and brought him to the ship’s safe room, according to the complaint.

He was transferred to the custody of the FBI, which brought him to New York on April 20.

Preska today granted a request from Philip Weinstein, one of Muse’s lawyers, for an extended period that would allow the defense team to investigate the case. She set the next hearing for Sept. 17.

In Isolation

Weinstein told Preska that his client had been held in isolation at Metropolitan Correctional Center, the federal jail in Lower Manhattan, since his arrest.

“He’s has been able to make just one single call for a minute,” to his mother in Somalia, Weinstein said. The defense lawyer said he was concerned about the severe conditions of Muse’s confinement, saying his client must undergo surgery after being stabbed in the hand by the Maersk ship’s crew during the incident and needs medication for an undisclosed condition which he declined to name.

Preska directed prosecutors to work with Weinstein and prison officials to help meet Muse’s medical needs.

“He’s isolated, he’s terrified, a boy who fishes and now he’s ended up in solitary confinement,” Deirdre von Dornum, another lawyer who is representing Muse, said outside court. “It’s a truly terrifying situation and he’s having a truly difficult time.”

Fiona Doherty, another Muse lawyer, told reporters after court that their client “will be exonerated,” adding, “Our client was only trying to find a peaceful resolution,” to the incident. “He was trying to negotiate for the safety of Captain Phillips.”

The case is U.S. v. Muse, U.S. District Court, Southern District of New York (Manhattan).

To contact the reporter on this story: Patricia Hurtado in New York federal court at pathurtado@bloomberg.net.

Last Updated: May 21, 2009 12:33 EDT