A THREE-DAY emotional rollercoaster for the Slovene people took another precipitous turn downward yesterday as the Yugoslav military took matters into its own hands.The military sent jets over this tiny Alpine region yesterday, after the independence-minded Slovenian government refused to capitulate to the Yugoslav Army. The action was reportedly taken without the authority of the federal government by the Army commander, Lt. Gen. Marko Negovanovic, and by a recently formed political party, made up mainly of hard-line Serbian Army officers. The Army's action appears to put into shambles, at least temporarily, the cease-fire negotiated last Friday by a European Community (EC) delegation which visited Belgrade and Zagreb, the capital of neighboring Croatia. In a statement released yesterday, the Army's party, whose leaders include the wife of hard-line Serbian President Slobodan Milosevic, called for the preservation of Yugoslavia and said that the Slovenian and Croatian declarations of independence last Tuesday put Yugoslavia "on the brink o f a major fratricidal war." Slovenian President Milan Kucan announced yesterday that Yugoslav Prime Minister Ante Markovic was flying to Ljubljana yesterday for talks with the Slovenian leadership. Neighboring Austria, meanwhile, called for a meeting within three days of the emergency intervention mechanism of the Conference on Security and Cooperation in Europe. These two developments, which came at press time yesterday, raise several questions: * How much authority does Mr. Markovic have with the federal Army at this time? * Will the EC suspend its nearly $1 billion in aid to Yugoslavia if the Yugoslav Army's attacks continue? (It proposed to do this if a cease-fire was not maintained.) * What is Mr. Milosevic's current relationship to the Yugoslav military's leaders? * Are the new mechanisms of the Conference on Security and Cooperation in Europe sufficently developed to help resolve this conflict? (The crisis prevention center, headquartered in Vienna, has been in existence only since February.) As fighting continued yesterday, Mr. Kucan said his government was "at war ... honoring the cease-fire ... and prepared to negotiate." Most military experts give Slovenia little chance of winning an all-out war, since its defenses are limited mainly to guns and small antitank weapons. Yet sources here disagree over the long-term authority of the Yugoslav military, since it is split among various ethnic factions and has little popular support outside the republic of Serbia. Some say the Army could split apart, pointing out that Fifth Army Commander Kondrad Kolcak is a Slovenian. Yet the military will make the difference in the short term, says Slovenian Liberal Democratic Party Vice President Slovan Zezec. "The terms we get with the military are the only important thing," Mr. Zezec says. "All else is negotiable. But I fear we haven't given them a way to save face so far." EC visit gave brief hope Before yesterday's hostilities, the EC delegation's visit to Zagreb was seen by many Slovene authorities as just the outside help - a tenuous but implicit recognition of their new status - they were hoping for. No country has yet recognized Slovenia's declaration of independence. Yet matters changed quickly over the weekend. Domestic Slovenian politics forced Kucan to back off concessions he appeared to make to the EC delegation to honor a 90-day "freeze" on the implementation of its independence declaration. In Slovenia, the impact of the unexpected hostilities - tank columns, crushed roadblocks, bombed airports, border fights, slain civilians - and an unexpectedly aggressive response by Slovenian territorial forces, have both shocked and overnight created a new political dynamic here. As Zvone Seruga, a popular Slovenian writer, put it: "The Slovenes had been hesitant about declaring independence. "But if there were doubts before, there aren't now. Now it's our Army and their Army, our boys and their boys. We feel like patriots." Deputy Foreign Minister Zoran Thaler told the Monitor, "After this brutality, it will be impossible for Slovenia to stay in Yugoslavia." People opposed cease-fire Such sentiments caused a popular outcry over the cease-fire agreement. It stressed the need for the flow of people and goods to continue to the outside world, and to keep the peace in Europe. Kucan was viewed by many as a "traitor" for even "raising the idea in Zagreb that Slovenia's declaration of independence is negotiable," says Anton Debler, a political scientist here. Kucan's tougher position gave military generals the opening they wanted to crack down, say sources. The atmosphere in this usually sedate and charming spired capital city was tense yesterday. The city was on air alert and sporadic outbreaks of machine-gun fire downtown, including a sabotage attempt on the National Assembly building, had emptied the streets. Rumors abound Information here is scattered and often incorrect. In a panic over a purported bombing run on the Press Center yesterday, Western reporters were shuttled toward a civil defense shelter, only to be called back when the attack turned out to be the starting up of the building's air conditioner. The West, and particularly the United States, has come under sharp popular attack from Slovenia for not coming sooner and more decisively to its aid. Yet many observers suggest Slovenia was unprepared for the events of the last few days. When asked in a press conference if he truly expected the West to come to his aid, Kucan said no. Two sentences later, however, he told reporters he was angry that the West had not helped.