An 18-year-old Somali accused of trying to hijack an oil tanker operated by a Japanese firm pleaded guilty Monday but denied playing a key role in the attack.

The defendant, whose name is being withheld because he is a minor, said during the lay judge trial at the Tokyo District Court that he only abetted the other three hijackers and did not fire any weapons during the raid off the eastern coast of Africa.

“I am not a pirate,” he told the court through an interpreter.

According to prosecutors, the Somali youth was the leader of the attempt on March 5, 2011, to take over the Guanabara, an oil tanker registered in the Bahamas and run by Mitsui O.S.K. Lines.

“This was nothing like the pirates we see in the movies,” the prosecutors said, pointing out that the attackers were armed with 19 automatic weapons and two rocket launchers.

The prosecutors said the four assailants fired their weapons once inside the tanker but failed to capture any of the 24 crew members, none of whom were Japanese. The crew quickly sealed themselves in a safe room and immediately sent an SOS.

A U.S. Marine Corps helicopter arrived at the scene around noon March 6, 2011, at which point the four Somalis surrendered. The U.S. military eventually turned them over to Japanese authorities.

The attempted hijacking was a vicious crime and the young defendant played the role of leader, the prosecutors said.

Of the four Somalis arrested over the incident, two have been sentenced to 10 years in prison. The fourth is still awaiting trial. The two convicted last week claimed that the minor played the main role and led the attack on the tanker.

The minor, who wore a black and gray jersey Monday, nodded occasionally to the interpreters during the court session. He told the court that he was born on May 11, 1994, and that at the time of the incident he was working as a mate for a local boat skipper.

He was initially sent to the Tokyo Family Court due to his age but was later indicted by prosecutors under the antipiracy law.

“The defendant was merely 16 years old at the time of the incident” and in no way did he play a leading role in the crime, one of his two lawyers said.

The Somali liked school but had to drop out when he was 12 due to his family’s low income, the attorney said. He then began working as a busboy and also caught fish to support his parents, she said.

The defendant was previously charged with being a pirate, but a Kenyan court found him not guilty, the lawyer said.

“Please consider the fact that he is still a minor, and try to think of what is best for his future,” the lawyer told the lay judges.

The ruling is set for Feb. 25.

More than 200 pirate attacks have occurred each year off the Somali coast since 2009, accounting for about half of the world’s total.

The Guanabara had taken preventive measures, including placing life-sized dummies holding fake weapons on its deck, though that didn’t stop the hijack attempt, the prosecutors said.

Japan enacted an antipiracy law in 2009 to hold captured pirates and put them on trial in Japanese courts. Those found guilty can face between five years and life in prison.