BELGRADE, Yugoslavia -- French President Francois Mitterrand staged a daring visit to embattled Sarajevo yesterday and vowed to break a Serbian blockade threatening the city's 300,000 trapped citizens with starvation.
Hours later, Serbian forces relinquished control of Sarajevo's shattered airport to United Nations peacekeepers so it can be reopened for humanitarian relief flights, the Tanjug news agency reported.
The first such flights, two French air force transport planes, each loaded with 6.5 tons of food and medicine, landed last night in Split on Croatia's Adriatic coast and planned to fly into the ravaged capital of Bosnia-Herzegovina this morning.
In Paris, the Defense Ministry announced that more such flights were being readied and would depart from France beginning today.
The apparent breakthrough generated only cautious optimism in beleaguered Sarajevo. U.N. officials said that formal reopening of the airport would take at least a week.
Nevertheless, hundreds of grateful Sarajevans braved a day out of their bunkers to thank Mr. Mitterrand for his initiative. Belgrade television showed tearful residents waving and blowing kisses from the debris-strewn sidewalks and chanting "Vive la France!"
Mr. Mitterrand, the first foreign leader to visit Bosnia since a Feb. 29 referendum endorsed independence and sparked Serbian rebellion, said that military force would be used if necessary to protect the relief flights and end the suffering brought on by the three-month siege that has killed thousands.
In another sign of the troubled times gripping the Balkans, Serbia's Crown Prince Alexander wore a flak jacket under his suit while addressing 100,000 protesters at a Belgrade demonstration against Serbian President Slobodan Milosevic.
"Victory will be ours. . . . Darkness and evil cannot win," declare the Yugoslav crown prince, who returned to his troubled land on Saturday for only the second time. "Long live democratic Serbia!"
It was the largest protest against Mr. Milosevic since he came to powerfour years ago. The Milosevic government is accused of fomenting ethnic warfare in neighboring Bosnia-Herzegovina and Croatia, which have seceded from the Yugoslav federation.
The gathering, which drew prominent religious, political and cultural figures, coincided with Serbia's most important national day, Vidovdan or St. Vitus' Day. On June 28, 1389, Serbs were TC defeated by Ottoman Turkey in the bloody Battle of Kosovo and lost their independence for the next 500 years.
More than two-thirds of Bosnian territory is now in the hands of Serbian guerrillas who have expelled Muslims and Croats since Bosnia left the Yugoslav federation in late February. Bosnian officials last week reported 7,440 confirmed deaths and 35,000 missing, many of whom are presumed dead since secession.
Yesterday's developments unfolded as the U.N. Security Council prepared for a previously scheduled session this morning, apparently poised to act quickly to launch a massive airlift of food and supplies if the truce holds as hoped.
Diplomatic sources said that if all parties appear to be meeting U.N. demands for a cease-fire, the council would probably assign Canadian troops already in the region to take charge of airport security and clear the cluttered runways.
The council session, set up late last week, initially had been slated to consider possible U.N. military intervention in Bosnia if the Serbs did not comply with a 48-hour truce deadline laid down Friday by U.N. Secretary-General Boutros Boutros-Ghali.
Western sources said Sunday that in view of Mr. Mitterrand's initiative, apparently undertaken without informing U.N. and other Western officials, it was unlikely that the council would consider a military operation.
"They ought to have a little more time," one diplomat said.
A glaring illustration of the dangers and complexities of th Bosnian conflict was provided yesterday when the French president was forced to take cover for a time in an airport building when gunfire erupted as he was preparing to leave Sarajevo after his five-hour visit.
Mr. Mitterrand, who visited a city deemed too dangerous for foreign mediators and armed U.N. peacekeepers, toured the artillery-pounded ruins of Sarajevo's historic center in the company of Bosnian President Alija Izetbegovic.
Mr. Mitterrand's dramatic mission was not announced until he was airborne from Lisbon, Portugal, where he and other European Community leaders met for a weekend summit. The gathering endorsed the use of military force to free Sarajevo airport, if needed, but failed to generate any specific proposals for lifting the siege.