President Violeta Barrios de Chamorro has announced plans to reduce the Nicaraguan army, the largest force in Central America, by half and retire some senior officers. Mrs. Chamorro, who took over after the leftist Sandinistas were defeated in free elections, said on Friday that the cutbacks would take effect by Aug. 3. Her spokesman, Antonio Lacayo, said the cuts would come mainly from sending draftees home and reducing the ranks of the militia. He said the reductions would also affect active-duty troops and reserve forces. Mrs. Chamorro did not say whether the Sandinista army chief, Gen. Humberto Ortega, would be among those senior officers who retire under the reforms. She had said earlier that Ortega, brother of former Sandinista President Daniel Ortega, would hold the post only temporarily. Ortega told reporters later that the army itself will decide which officers stay and which leave. Mrs. Chamorro also said she was ordering the army and the Interior Ministry to disarm civilians. ``It is my purpose that by Christmas there are no weapons in the hands of anyone unless they are part of the nation's army,'' Mrs. Chamorro said. She said draftees would be home by Dec. 7. The president's announcement came in a speech to the Cabinet, representatives of the United Nations and the Organization of American States, the diplomatic corps and the army general staff. During the 10 years of Sandinista rule, Nicaragua never made public the size of the army, but estimates put its strength at near 55,000, making it the largest in Central America. Gen. Ortega said on Friday that the army numbered 96,000, but it was not clear how many of those were active-duty troops and how many were reservists. Lacayo said the army numbered 80,000, including reserves, militia and draftees, when Mrs. Chamorro took office in April. The president said the cutbacks would bring the army strength to ``less than 41,000 men and women,'' adding: ``This means half of the members that it had on April 25, the day I assumed the presidency of the republic.'' Mrs. Chamorro also announced that 14,200 of the U.S.-backed Contra rebels have demobilized so far. The Contras waged a nearly decade-long insurgency against the Sandinistas. ``With all security we can say that today the war has been left behind,'' Mrs. Chamorro said. About 1,000 Contras have yet to demobilize but are expected to do so, she said. The measures were announced before Mrs. Chamorro left for a regional weekend summit in Guatemala, also to be attended by Secretary of State James A. Baker III. It will be Mrs. Chamorro's first summit as president. Mrs. Chamorro later arrived in Guatemala. The summit, which is taking place in the town of Antigua, 30 miles west of Guatemala City, is expected to concentrate on efforts to reconstruct the economies of Nicaragua and other countries in the region. She wanted to present the army reduction plan and the Contra demobilization as evidence that her 7-week-old, U.S. backed government is fulfilling regional peace pacts entered into by her predecessor. Mrs. Chamorro had ordered Gen. Ortega to present her with a troop-reduction plan, but she did not say whether the plan she announced was his.