The communist-led Yugoslav army and the secession-minded Croatian government Saturday drew back from "the edge of civil war," implementing an accord taking troops off combat readiness and demobilizing Croatian reserve police.

Amid the conciliatory moves, however, the federal Ministry of Defense in Belgrade defended the authenticity of a film purportedly of secret meetings by Croatian officials plotting insurrection, adding it would pursue "legal proceedings." Croatian officials denounced the film as fraudulent.Some 60,000 Croatians rallied in chilly weather in support of their nationalist government in a central square of the republic's capital of Zagreb, 250 miles northwest of Belgrade, chanting to Croatian officials "Call on us, we will give our lives for you."

Similar gatherings were reported throughout the republic.

Speaking to the Zagreb rally, Yugoslav Vice President Stipe Mesic, the Croatian representative on Yugoslavia's eight-man collective presidency, sought to soothe tensions.

"... I promise that an era of peace, work, and democracy has come, when nobody is to give conditions to Croatia on what to do in the future," he said. "I appeal to you to go back to your everyday jobs, but to remain ready in case somebody makes an attempt to impose their solutions on us by force."

The developments came hours after marathon negotiations in Belgrade led by the collective presidency ended in an agreement to avert a potentially bloody showdown between the military and Croatian police forces deployed to resist any intervention by troops.

Croatian President Franjo Tudjman announced his government fulfilled its end of the agreement, "demobilizing" at noon some 21,000 reserve police that were deployed with 22,000 regular officers to resist the army.