Defense Secretary Richard B. Cheney yesterday signed an order giving the Army authority to freeze the departures of officers and enlisted personnel from the service.

The order is designed to make sure the Army has enough trained personnel to meet the needs of the Persian Gulf deployment and to preserve the cohesiveness of units elsewhere in the world so they could respond to future emergencies, officials said.

The order expands the freeze already imposed on officers and enlisted personnel stationed in the Persian Gulf region. The new authority applies to soldiers elsewhere in the world and will mean that about 5,500 people per month who otherwise would have left the Army will be forced to stay on indefinitely, officials said.

Not only does the expanded freeze order keep in uniform officers who would have retired or enlisted people who have fulfilled their terms of duty, but it also halts transfers of most personnel from one region to another, such as from a European base to a job in the United States, officials said.

Army officials said there are three exceptions to the mandatory extensions of service: officers who face mandatory retirement for medical or other reasons; soldiers discharged for reasons of incompetence or other failings; and hardship cases.

President Bush's decision last month to double the U.S. deployment in the gulf region to more than 400,000 soldiers, sailors, airmen and Marines has prompted military personnel officers to assess whether there are enough trained reinforcements to replace the wounded and killed if war should break out in the Persian Gulf.

The Army is the first to issue such a comprehensive hold order, Pentagon officials said. The Marine Corps yesterday disclosed that it invoked a measure on Nov. 8 that means as many as 12,000 Marines, both regular and reserve, could be prevented from leaving the service. But unlike the Army, the Marines will not apply the measure service-wide, a spokeswoman said.

The Navy and Air Force are reported to be considering whether to issue similar freeze orders.