While Bosnia Suffers Serbs block relief columns and continue to defy U.N. flight bans

AS THE INTERNATIONAL COMMUNITY dithered on the margins of the crisis in Yugoslavia, the anguish continued in beleaguered Bosnia-Herzegovina. An aid convoy bound for the town of Srebenica, where some 80,000 Muslims have been trapped by fighting for months, was blocked at the Serbian border for days by Serb militiamen and angry, jeering civilians. A convoy to Goradze was delayed after an escorting personnel carrier hit a mine.

The ban on military flights over Bosnia, imposed by the U.N. early last month, has been violated more than 100 times, according to a U.N. commander. Western diplomats said Serbs have used military helicopters to ferry troops and supplies, even as NATO officials in Brussels contemplate plans for enforcing the ban. Fear of fighting yet to come compelled the Security Council to approve sending monitors to Macedonia, and President Bush urged the same for neighboring Kosovo, where tensions are high between Serbs and the ethnic Albanian majority. A shipment of construction material did reach Montenegro to prevent some 7 million tons of toxic sludge from breaking through a dangerously weakened dam and flowing into the Danube River system.