SARAJEVO -- Thousands of Serb refugees fled for safety in central Bosnia as fighting continued between the Moslem-led Bosnian army and Serb forces, lending weight to reports that the Moslems had gained ground. Fighting between the Bosnian Serb and the mostly Moslem Bosnian armies forced thousands of Serb civilians to seek refuge in villages outside the town of Vozuca near Mount Ozren. A local Red Cross official from the rural area said Tuesday that 5,000 refugees had fled in the past five days. Serb military sources said the Moslem forces had gained ground and captured a village east of Zavidovici. The UN could not confirm the report. Major Serb retaliation would seriously jeopardize the already tenuous cease-fire brokered by the UN which went into effect June 10. The truce has calmed fighting along frontlines separating Serbs from Moslem-Croat allies but cease-fire violations have increased in recent days.