CAMP PENDLETON, Calif. -- Under a new rule change made by the Marine Corps, service members as young as 18 are allowed to drink alcohol on Camp Pendleton and other Marine bases on special occasions, it was reported Friday.

The decision has been cheered by some Marines but has upset anti-drinking groups, the North County Times reported.

The rule was released April 19 and signed by Marine Corps Commandant Gen. James Conway, a commandant spokesman told the Times Friday.

It changes the service's drinking regulations to allow Marines who are at least 18 years old to drink on base on occasions designated by commanders, including the popular Marine Corps birthday celebrations and welcome-home parties after combat deployments, the Times reported.

The minimum drinking age in California is 21.

A 1995 Defense Department directive required that the minimum drinking age on any DOD installation "shall be consistent with the age established by the law of that state as the state minimum drinking age."

While the measure has taken effect at Camp Pendleton, there have been no events held under the new rule yet. But Marines told the newspaper they were looking forward to being able to consume alcohol legally on special occasions.

However, the decision has upset some groups, such as Mothers Against Drunk Driving, which said the Marine Corps is making a big mistake.

"We would hate to see a mother or father lose their child here on American soil in an alcohol-related crash or injure somebody else while impaired," Pat Hodgkin, the group's executive director, told the newspaper.