Armed Argentine civilians took over a small military base near Buenos Aires Monday after a gun battle with soldiers that left five people dead, an official news report said. The Ministry of Defense, anticipating a possible fourth insurrection against the government in the past 21 months, bolstered defenses at Government House and the official residence of President Raul Alfonsin, according to the state-run Telam news agency. The civilian president spoke by telephone with Defense Minister Horacio Jaunarena and Army Chief Gen. Francisco Gassino and told them to retake the base.