Two sailors attached to Sasebo security forces face possible punishment for their alleged roles in dumping more than 3,000 rounds of ammunition in waters around U.S. Navy facilities in southern Japan, the Navy said Monday.

A second class petty officer, who admitted in October to placing shotgun and M16 rounds in three places near the facilities while on duty, faces an administrative hearing, said Sasebo Naval Base spokesman Charles Howard.

The second sailor, a first class petty officer whose job includes overseeing ammunition, faces a dereliction of duty charge in a special court-martial, Howard said.

The sailor may face more charges, he said. The date of the court-martial had not been set as of Monday.

Howard said the first class petty officer, a gunners mate, faces a harsher military disciplinary tract because of his position as an ammunition supervisor.

"There was a senior person in the position to make the call," Howard said.

Navy officials withheld the names of both sailors, who are assigned to the security department at Commander Fleet Activities Sasebo.

The military typically does not release the names of servicemembers facing non-judicial punishment in administrative hearings.

Howard said the name of the first class petty officer would be released at the time of the court-martial.

The motivation for the dumping remained unclear Monday, Howard said.

It also was unclear if the senior sailor was the junior sailor’s direct supervisor.

The ammunition — 3,000 shotgun rounds and 335 rounds of 5.56 mm ammunition — was found Oct. 27 in waters near Hario-shima, the Maebata ordnance facility and the Akasaki fuel pier, which are near U.S. Navy facilities in Sasebo.

The second class petty officer, who is a master-at-arms, admitted to bagging the ammunition and dumping it in the three places.

The ammunition was supposed to be used in firing exercises.

Navy divers spent two days in the waters to retrieve the ammunition and believe they recovered it all, Howard said.

Sasebo city officials on Monday were surprised to learn two sailors were being accused of the unauthorized disposal.

But a spokesman said the city was pleased at the Navy’s reaction.

"While such an incident should have never happened, we feel that the military responded quickly in recovering the ammunition," said Akihiro Yoshida, a spokesman for the city’s Military Affairs Bureau.

"Because all the munitions were removed and that the site was within the restricted area," he said, "we do not believe that the incident would further endanger the public’s safety."

Chiyomi Sumida contributed to this story.