Street Riots Flare Again in Belgrade : Yugoslavia: A second wave of militant students defies tight security. They oppose the government of hard-line Communists.

Despite a tight security lid clamped on the Yugoslav capital Sunday, thousands of angry students took to the streets of Belgrade for a second wave of rioting in a daring challenge to the hard-line Communist leadership.

Belgrade police fired tear gas at the crowd of at least 3,000 students who marched on the government-controlled television station early today after most federal tanks and troops had withdrawn, leaving the city under heavily armed guard by hundreds of police in riot gear.

A day after the worst rioting in Belgrade since the Communist takeover in 1945, police and paramilitary forces had maintained a tense calm during the daylight hours by rounding up opposition leaders and chasing pedestrians from the debris-littered streets.

Shortly after midnight, students began pouring out of Belgrade University dormitories to protest the arrest of at least 180 anti-Communist activists who had organized the rally Saturday that erupted in violence after police stormed the gathering in Republic Square.

The second outburst of anti-government unrest suggested that pressure on the Serbian leadership, one of Eastern Europe’s last bastions of communism, would continue despite the strong show of force displayed Sunday.

Saturday’s protest was the first serious indication of broadening disenchantment with the Serbian leadership. By attempting to disperse the rally with brute force and then summoning federal troops and tanks, Serbian President Slobodan Milosevic has demonstrated he will seek to hold on to power at any cost.

The embattled Serbian leadership countered the civil unrest by staging several rallies in support of Milosevic, while simultaneously preventing any public assembly of opposition supporters.

Legions of police and paramilitary troops hauled off anyone lingering on the streets for more than a few seconds.

Serbian opposition forces and officials in other parts of Yugoslavia were quick to condemn the government’s use of force against demonstrators, which triggered the daylong fighting that killed a policeman and a protester and injured 76 others.

The Serbian Interior Ministry reported 180 arrests following the rioting, including former presidential candidate Vuk Draskovic of the Serbian Renewal Movement.

Opposition parties announced they would withdraw from the Communist-dominated Serbian Assembly in protest of the harsh crackdown on dissenters. Nineteen non-Communist deputies began a hunger strike.

The federal army began withdrawing its tanks and troops late Sunday, probably in an effort to facilitate a return to normal to encourage workers to show up at their factories and offices today.

An emergency meeting of the eight-man federal presidency issued a vague warning against future unrest, stating that Serbia was empowered to “use all constitutional means to preserve the peace.”

The Slovenian and Croatian representatives boycotted the meeting, highlighting the internal divisions undermining federal authority in fractured Yugoslavia.

Slovenia’s delegate to the collective presidency, Janez Drnovsek, suggested that a meeting of federal and republic leaders set for Tuesday in Belgrade be relocated to the Slovenian capital of Ljubljana.

Belgrade is the capital of both Serbia and the federal government.

Croatia and Slovenia have recently taken steps to pull out of the Yugoslav federation they helped create in 1918. The two most developed and Westernized republics claim they are being drained by the impoverished south and the need to support a federal government that spends nearly two-thirds of its revenues on the armed forces.

The talks set for Tuesday are part of a series of attempts at negotiating a new alliance among the fractious republics, although six previous rounds have been fruitless.

Free-lance journalist Michael Montgomery reported from Belgrade, and Times staff writer Carol J. Williams from Budapest.