ASSOCIATED PRESS WRITER

DAVID CRARY

SARAJEVO, Bosnia-Herzegovina (AP)—As many as 32,000 people could be forced into a perilous dash into Sarajevo if advancing Serb forces capture a strategic mountain overlooking the city’s airport, a U.N. official said today.

Heavy combat has raged for several days on Mount Igman as troops of Bosnia’s Muslim-led government try to hold off a Serb offensive backed by tanks. Sarajevo radio said the heaviest fighting today was on the west side of the mountain, overlooking the town of Hadzici, west of central Sarajevo.

Meanwhile, the European Community agreed today to threaten neighboring Croatia with limited economic sanctions if the Zagreb government doesn’t stop ‘‘ethnic cleansing’‘ and attacks on Muslims by ethnic Croats in Bosnia. At Germany’s insistence, the bloc stopped short of immediately ordering sanctions.

The United Nations has accused Bosnian Croats of launching a second wave of forcible expulsions of Muslims from western Bosnia, as Serbs have done in the east and north. Croatian radio reported heavy fighting today between Croats and Bosnian government forces in Bugojno, 50 miles west of Sarajevo, and U.N. officials said Croats and Muslims battled Sunday in the central city of Vitez.

Peter Kessler, a U.N. aid official, said residents and refugees living on or near Mount Igman feared the Serbs would sweep through their towns, leaving them no choice but to flee across the U.N.-controlled airport into besieged Sarajevo.

The airport is exposed to Serb sniper fire, and scores of people have been killed in nightly dashes across the clandestine route—the only way in or out of the besieged city.

Crossing the airport runway is also the principal route by which Sarajevo’s defenders get supplies of weapons and ammunition. Even this modest flow would be cut if Igman fell.

Kessler said thousands of people would try to rush into Dobrinja, a government-held Sarajevo suburb on the other side of the airport. Neither heavily shelled Dobrinja nor the rest of Sarajevo, which is without water and electricity, have the capacity to handle new refugees, he said.

‘‘It could be a staggering event, very tragic,’‘ he said.

Another drama was unfolding in the village of Fojnica, west of Sarajevo, where a U.N. military patrol late Sunday found 230 mental patients who had been abandoned for three days after the staff fled during fighting.

Fojnica was captured last week by Bosnian government troops, who chased out Bosnian Croat militia units and thousands of Croat civilians. The part of town around the mental institute was deserted except for the patients, 100 of them children, said Maj. Luuk Niessen, a spokesman for the U.N. peace keepers.

Niessen said even the adult patients at the institute could barely feed themselves, and five small children were in critical condition. Gunfire from an unknown origin was aimed at the institute while the U.N. peace keepers were there, but no one was hurt, Niessen said.

Kessler said relief workers were heading to the institute today with milk powder and baby food. Some of the patients had been locked in their rooms for three days, he said.

‘‘The situation is said to be very, very bad,’‘ Kessler said. ‘‘These are children left alone in the middle of a war.’‘

At least 138,000 people have been killed or declared missing as a result of the fighting, which broke out in April 1992 when Bosnian Serbs rebelled against a vote by Muslims and Croats to secede from Serb-dominated Yugoslavia.