SARAJEVO -- Bosnian Serbs promised Tuesday to reopen supply roads into Sarajevo this week to revive a ceasefire agreement stalled by bickering over a demilitarized zone near the capital.


The pledge was given by an aide to Bosnian Serb leader Radovan Karadzic despite Serb insistence that Moslem-led government troops have not pulled out of the zone.


"Despite the fact that the Moslems keep refusing to withdraw their forces from the illegally-occupied ground on Mount Igman and Mount Bjelasnica, the Serbs are ... going to open up the routes for civilian traffic in and out of Sarajevo by the end of the week," Jovan Zametica told the Bosnian Serb news agency SRNA.


The issue of withdrawal of the government army from the Mount Igman demilitarized zone around Sarajevo has stalled a four-month cessation of hostilities accord signed by the opposing sides on New Year's eve.


Zametica said Serbs were reopening the roads "to save the four-month agreement ... but also to ensure that humanitarian aid is reaching all the innocent civilians in this terrible war."


The Serbs had refused to reopen the vital supply routes until Moslem forces left the demilitarized zone.


Serbs briefly reopened the routes last year, giving the 380,000 residents of the besieged Bosnian capital a taste of a more normal life.


The UN commander in Bosnia, General Sir Michael Rose, told Bosnian Serb army chief General Ratko Mladic over the weekend that Moslem-led forces had vacated the zone.


But the UN could not verify the withdrawal Monday when a Bosnian guide refused to lead them to the last known hideout, arguing it was unsafe to travel on foot in the deep snow.


UN spokesman Major Herve Gourmelon said Bosnia's fronts had remained quiet over the past 24 hours with just eight confirmed ceasefire violations -- seven by the Bosnian Serbs alone and one involving both sides. He said the Bihac enclave in northwestern Bosnia was calm overall with only a few small bursts of gunfire near Bihac town.


The enclave has been one of the few areas in Bosnia to see fighting since the truce came into force on Jan. 1.


Gourmelon said a planned visit by Rose to Knin, the stronghold of the rebel Serbs from the Krajina region in Croatia, to persuade them to withdraw from the enclave had been postponed "for technical reasons."


Krajina Serbs joined Bosnian Serbs and rebel Moslems in an offensive on Bihac in November. Neither the Croatian Serbs nor rebel Moslems have signed the latest Bosnia truce.


Officials of the Contact Group -- the United States, Russia, France, Britain and Germany -- met in Paris on Tuesday to discuss ways of consolidating the fragile ceasefire and relaunching peace negotiations.


U.S. Assistant Secretary of State Richard Holbrooke, just back from Sarajevo, told the group he had encountered bitter criticism from Bosnian Prime Minister Haris Silajdzic on Monday after saying the Contact Group's peace plan was a starting point for new negotiations.