Serbian TV broadcast damage in Belgrade reportedly from NATO air strikes  ALSO: Refugee crisis builds as Serbs reportedly target Kosovars Clinton orders reinforcements to Macedonia Milosevic gets bird's eye view of the new NATO IMAGE GALLERY: NATO strikes Yugoslavia: Day One  MESSAGE BOARD Crisis in Kosovo

March 27, 1999
Web posted at: 9:59 a.m. EST (1459 GMT)

BELGRADE, Yugoslavia (CNN) -- Yugoslavia's capital braced for a fourth day of NATO airstrikes as allied troops in neighboring Bosnia-Herzegovina watched the skies for new incursions by Yugoslav aircraft.

Friday's attacks found targets around Belgrade, sending fireballs shooting into the night sky and shattering windows around the city. The raids were the heaviest and closest to the city's center since airstrikes began Wednesday.

In three days of attacks, Belgrade has become a shadow of its former self. Main streets are largely deserted.

Many in Belgrade took cover in underground shelters. Their fears were compounded by reports that a factory had been hit and was spewing toxic fumes into the air.

Yugoslav authorities insisted it was the result of a strike on a civilian pharmaceutical plant: NATO said the escaping fumes may have come from a factory that produced missile and rocket fuel.

Another NATO strike set fire to a forest close to a popular Belgrade suburb.

NATO resolve 'absolute'

NATO hopes the raids will force Yugoslav President Slobodan Milosevic to sign a peace agreement that will end a year of ethnic strife in the Serb province of Kosovo.

NATO officials say the Yugoslav offensive in Kosovo must stop before the bombing ends.

"NATO's resolve to continue this operation until our objectives are met remains absolute," NATO spokesman Jamie Shea said in Brussels on Saturday.

Yugoslavian media claim the bomb and missile attacks have inflicted numerous -- but unspecified -- casualties. Authorities in Belgrade claim the attacks have created a humanitarian catastrophe with damage to homes, schools, hospitals and infrastructure such as water supply networks.

Marines head to protective bunnkers in Bosnia after the approach of two Serb helicopters triggered air raid sirens

Fuel supplies are restricted to a few priority users such as hospitals and public transportation. City buses and trams are still running, but few people are traveling.

New alert for NATO's Bosnian force

NATO forces in Bosnia, meanwhile, were on alert Saturday after reports that two Yugoslav helicopters crossed the border Saturday.

The helicopters left Bosnian airspace without incident, but not before triggering air raid sirens at the NATO base at Tuzla, a spokesman for NATO's Stabilization Force in Bosnia said.

Saturday's alert at Tuzla came after NATO fighters shot down two Yugoslav jet fighters that crossed into Bosnia on Friday evening. The pilots of those planes were unaccounted for early Saturday, said U.S. Army Maj. Tom Evans, an SFOR spokesman.

Wreckage from a Yugoslavian MiG-29 shot down after it violated Bosnian air space

"We are working with local police to attempt to find the pilots," Evans said.

NATO says troops could be next targets

The forays into Bosnia come as reports mounted that the Serbian-led military has intensified assaults against Kosovar Albanian guerrillas and civilians.

U.S. Gen. Wesley Clark, NATO's supreme commander, said Friday that new NATO attacks would focus on Serb troops. He said the current campaign was "systematically and progressively" wearing down Yugoslavia's military capability and that troop columns could be hit next.

But Clark said NATO air power alone could not stop the Yugoslav army and Serb paramilitaries from carrying out attacks in Kosovo.

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