Both crises revolve around freedom of movement - or the lack of it - for the UN and civilians trapped in war zones. 'The situation is very difficult and has not been resolved yet,' said Paul Risley, a UN spokesman. 'I think we have big problems.'
Serbian officials in Pale eventually granted permission for a limited resupply convoy to Zepa and Gorazde, where UN troops can no longer operate.
The fuel embargo would remain, the Serbian authorities said, until the Bosnian government cleared around 500 soldiers from the DMZ on Mount Igman, west of Sarajevo.
The government troops began to pull out at noon, but political leaders in Sarajevo said a full withdrawal would depend on UN action to secure a road over Mount Igman into the city. Yesterday, French troops were fired on twice, 'almost certainly' by Bosnian government forces, the UN said.
Troops monitoring the withdrawal were attacked with a rocket-propelled grenade, and returned fire two hours after an engineering vehicle came under small arms fire. There were no immediate reports of casualties, but the situation was unclear last night.
Yasushi Akashi, the UN envoy, visited Sarajevo and Pale for talks on Saturday, winning agreement for the DMZ withdrawal and the dispatch, through Serb-held territory, of 11 fuel convoys to personnel in Sarajevo and the three eastern Muslim enclaves, Gorazde, Zepa and Srebrenica. But the Serbian decision was reversed on Sunday. An outraged Mr Akashi finally extracted a promise that two convoys could travel today.
A total of 20 tons of fuel should be delivered to Zepa and Gorazde, where British peace-keepers have been forced to break into emergency supplies.
'That's enough for a couple of days' supply at most,' Mr Risley said. 'That does not meet assurances (Radovan) Karadzic gave us on Saturday.'
One problem is that the fuel ban was imposed by General Ratko Mladic, the Bosnian Serb commander, who failed to attend the meeting on Saturday.
General Sir Michael Rose, the UN chief in Bosnia, is seeking talks with General Mladic to resolve the issue, and officials hope the embargo will end if the Bosnian troops leave Mount Igman. Officials in Pale complain that enemy forces are using the DMZ to launch attacks on Serbian troops.
Yesterday the Bosnian Serb army said 11 soldiers were killed and 11 wounded in a government attack close to the zone on Saturday.
The UN was investigating reports of the incident, but had no details. French peace-keepers patrol the DMZ to discourage such activities, but say that in such steep, wooded ground it is easy for small groups to move about undetected. Two weeks ago, Bosnian commandos attacked a Serb post near Igman, killing 16 soldiers and four nurses, an action the Serbs characterised as an atrocity. Their response to the latest attack was muted, perhaps out of embarrassment at such loses in such a short time.
In return for clearing the DMZ, created in August 1993 after Serb forces overran Mount Igman and withdrew under threat of Nato air strikes, the Bosnian government wants the UN to protect the Igman road from Serb gunners.
The rough track from Tarcin to Hrasnica, west of Sarajevo, is the only land route into the city.
Bosnians who travel the dangerous lower stretch do so at night, without headlights, or on foot. They must then go through a tunnel under the UN-controlled airport, to reach Dobrinja, a government- held suburb. For a few weeks, civilians were able to use the 'Blue Routes' across the airport to pass between government and Serb-held areas, but the Serbs ordered the UN to close these routes in July.