Muslim-led Bosnian government forces made virtually no progress last week in their offensive against the Bosnian Serbs besieging Sarajevo, military commanders on both sides said yesterday. They said the offensive, launched last Thursday and interpreted by some hopeful Sarajevans as an attempt to lift the 38-month-old siege, had more or less fizzled out inside four days after meeting firm Bosnian Serb resistance.

A Bosnian Croat brigadier, Vinko Lucic, whose forces are allied to the Muslim-led armies, said the Bosnian Serbs had stopped the offensive with artillery fire and large amounts of anti-personnel mines. However, even in mountainous areas where the Bosnian Serbs' superiority in heavy weaponry was less effective, the Muslim-led forces failed to break through.

Nonetheless, Brigadier Lucic described the attacks as a prelude to a more sustained government effort, intended to last for more than a month. He maintains that the Bosnian Serbs are seriously overstretched and, if subjected to concerted attack from several directions, will have to retreat.

Predictably, both sides' official communiques since Thursday have claimed successes. The Bosnian Serb commander, General Ratko Mladic, broke a public silence of several weeks yesterday to praise his men for "stopping the enemy offensive, holding your defence lines firm and inflicting heavy casualties on the attackers".

One sign that the Muslims' offensive may not have gone well is that United Nations staff were prevented from visiting Bosnian army field hospitals. No complete casualty figures have been issued.

Western intelligence sources consider the Bosnian government forces to have suffered something of a bloody nose. Perhaps not coincidentally, several Western governments had publicly advised against the offensive. The consensus of Western government opinion is that the Muslim-led forces are becoming better armed and trained but lack the strength to relieve Sarajevo. According to two separate recent intelligence assessments, the Muslim-led forces possess only 45 to 50 tanks, while the Bosnian Serbs have 400. The Bosnian Serbs retain a clear advantage in mortars, artillery and fixed-wing aircraft, but have only 75,000 to 80,000 men compared with the government's 120,000.

Convoys reach city, page 13