FROM a second-floor alcove of former Communist Party headquarters, Radio Knin blares out Serbian nationalist songs, behind windows festooned with red, white, and blue Yugoslav flags. Inside, in a makeshift control room lined with egg cartons to absorb sound, volunteers scoop up sheaves of papers from a fax machine and pile them on a lace-covered table nearby, where a broadcaster is about to read the latest news from Belgrade.
``The radio is the only source of information Serbs can rely on here,'' says Lazar Mazura, Knin's deputy mayor and a spokesman for the minority Serbs in this remote region of Croatia.
Knin, center of the 500,000 Serbian minority in Croatia, has become increasingly militant as tensions in the fractious Balkan federation of six republics and two provinces have increased.
Until a few weeks ago, roads leading into this rugged mountain town near the Adriatic coast were blocked by tractors and armed men, fearful of a Croatian militia attack. With Yugoslavia on the brink of disintegration, Knin has become a simulacrum of the hatreds and fears that continue to divide the region.
So far, a major outbreak of violence has been just narrowly avoided, although a day rarely passes without another bout of brinksmanship. The survival of Yugoslavia, a nation consisting of a patchwork of ethnic groups and religions, has been increasingly in the balance as old rivalries surface following the demise of strict Communist controls.
Croatia and neighboring Slovenia, where center-right governments won power in elections last year, are at odds with Serbia, Yugoslavia's largest, Communist-ruled republic, which they accuse of dominating the country politically and economically since its creation in 1918.
The Serbs in Croatia accuse the new government in Zagreb, Croatia's capital, of discriminating against them. The Croatian government counters that the unrest has been orchestrated by the Serbian government in Belgrade and contends that Serbs have no right to demand political autonomy while they deny the rights of Albanians in Serbia's Kosovo Province.
Most Yugoslavs now believe the issue is not whether the country will break up, but whether the process can be achieved without bloodshed.
Pro-Western Slovenia, the nation's most prosperous republic, and Croatia plan to break away from Yugoslavia if the brittle federation is not turned into a loose association of near-independent states. After the collapse of yet another round of talks to preserve unity last week, Slovenian officials demanded that financial accounts be settled among the nation's republics, as a prelude to secession. Yugoslavia is governed by an eight-member federal presidency made up of representatives from the country's six republics and two provinces.
The secessionist moves by Slovenia and Croatia have been rejected by Serbia, which seeks strong centralized rule. Serbia has also threatened to expand its borders to absorb all Serbs in other republics if the current federation breaks up. That also worries Bosnia and Herzegovina and Macedonia, where large Serb and Croat minorities exist.
In Knin, Serbs say they want no part of an independent Croatian state and have threatened to fight unless Zagreb acknowledges their demands for full autonomy.
``If Croatia can give us no guarantees of our civil rights, we will be forced to guarantee them ourselves, together with all Serbs in Yugoslavia,'' Mr. Mazura says. ``Croatia can go where it pleases, but we're not going along. If we must we shall ask the Yugoslav Army to help us.''
The Yugoslav Army, in which Serbian officers are a majority, has often said it will defend national unity. Its differences with Croatia have dragged the country to the brink of civil war several times in recent weeks.
Yugoslavia came closest to civil war late last month, when Croatia and the People's Army appeared set to clash over a federal order to disarm Croatia's reserve police force. Tensions abated only after Croatia disarmed the units and the Army ended a combat alert. Yet they continue to simmer.
Tempers flared again over the weekend when the federal Army ordered its troops to arrest Croatian Defense Minister Martin Spegelj for allegedly planning a rebellion against Yugoslavia that involved the killing of Army officers. Mr. Spegelj is believed holed up in a house in Zagreb, guarded by dozens of heavily armed security guards.
Any attempt to seize Spegelj would lead to a rapid, bloody escalation, says Mario Nobilo, an adviser to Croatian President Franjo Tudjman.
``Any attempt to arrest Mr. Spegelj by commando units, I expect, would be automatically followed immediately by military intervention in Croatia,'' he says. Such an intervention, he adds, would prompt Croatia to invoke a defense accord with Slovenia.
In a secret Army video shown on Belgrade television last month, Spegelj purportedly sought ``physical liquidation of Army officers and their families.''
The film accused Spegelj and others of illegally importing weapons from Hungary, allegedly to create an independent Croatian army. The Hungarian government has confirmed the sale of about 10,000 automatic rifles to a Croatian trading company. Spegelj has called the film ``a monstrous frame-up'' designed to destabilize Croatia's leadership.
The traditional rivalry between Serbia and Croatia is compounded by sharp ideological differences over the future course of economic reforms, including privatization, foreign ownership of companies, and eventual integration in the European Community, all of which Serbia opposes. Much of Yugoslavia's lossmaking, state-run heavy industry is located in Serbia. Slobodan Milosevic, Serbia's hard-line communist president, has fiercely attacked the reforms, saying they are pushing Serbia ``toward complete economic collapse.''
To make matters worse, the historical differences and conflicts between the two ethnic groups continue. Serbs brand Zagreb's new government as ``Ustasha Fascists,'' a reference to the Nazi puppet government set up by Croatian fascists in World War II. Tens of thousands died in bitter fighting between the two peoples.