Argentine Army headquarters announced today that an attempt to oust Commander-in-Chief Roberto Viola had been put down, but the rightist general heading the rebellion later threatened to lead a handful of holdout troops into the central city of Cordoba.

Gen. Luciano Menendez, commander of the Third Army Division with headquarters in Cordoba, officially was dismissed from his post after broadcasting a statement that accused Viola of "inadmissable tolerance" toward "Marxist subversion" and demanded the Army commander's ouster.

Military sources have provided conflicting reports on the situation in Cordoba, the country's third largest city, 470 miles northwest of Buenos Aires.

Spokesmen first said Menendez had been arrested, but a communique from military headquarters later said that the general had refused to accept his dismissal and was holding on with a small group of followers at Jesus Maria, a town just outside the city of Cordoba.

Gen. Menendez, leader of a hard-line faction that wants a further government clampdown on leftist activities, apparently was enfuriated by the military government's decision this week to release Jacobo Timerman, former publisher of the influential Buenos Aiers newspaper La Opinion.

Timerman, stripped of his Argentine citizenship and expelled from the country on Tuesday, was released after being held without charges in jail and then under house arrest for more than two years.