Fleeing the insurgency, millions of Mozambicans have won some measure of security in an archipelago of Government-held cities and towns.

Much of the population has swarmed into an archipelago of Government-held cities and towns.

Serbian nationalist leaders have contended that many Serbs in Tuzla, as well as in other Government-held cities, including Sarajevo, are "ethnic hostages," prevented from leaving because they are Serbs.

The refusal has severely strained the transport of troops to Asmara, the besieged, Government-held northern city and the staging point for efforts to retake the port of Massawa.

Six NATO F-16 fighters dropped 10 laser-guided bombs and four rockets on a Serbian command and control bunker near the Government-held city of Tuzla.

As summer draws to an end, the prospect is for another winter with the rebels camped in the country's deserts, valleys and mountains, apparently unable to capture Kabul, the capital, and two dozen other Government-held cities.

But an outside world that has chosen neither to impose a peace settlement nor to enforce U.N. resolutions protecting civilians in Government-held cities is obliged to restrain its criticisms of Bosnia's decision to resume fighting.

Although the guerrillas have failed to capture a single Government-held city since the Soviet army completed its withdrawal in February, the Bush Administration apparently thinks they should strengthen their bargaining position by scoring new victories.

There have been fears that rebels witll try to stop relief supplies from reaching Government-held cities.

Those Serbian tanks, hidden within the Sarajevo "exclusion zone," moved out this week to join the siege of two other Government-held cities, Maglaj and Tuzla.