A UN spokesman detailed a list of violations by both parties, including artillery attacks, detention of UN personnel and the ban by Bosnian Serbs on urgently needed fuel convoys. Lieutenant-General Sir Michael Rose, the UN commander, said he believed 'the strategic balance is turning against the Bonsian Serb army. There may come a moment when the Bosnian government perceives that it is in its interest to return to full-scale war. If it did so in the short term, it would be a catastrophe for the people of this country'.
The Bosnian Serb leader, Radovan Karadzic, declared a 'state of war' in the Bihac region in northwestern Bosnia where government troops have encircled the Serb-held town of Bosanska Krupa.
In a government offensive near Sarajevo, Bosnian soldiers yesterday infiltrated a demilitarised zone on Mount Igman, west of Sarajevo, to launch an attack on Serbian troops outside the zone. The Bosnian army shelled a French observation post on Mount Igman, prompting a swift warning that Nato will carriy out air strikes if the action is repeated.
In possible Serbian retaliation for the government offensives, several rounds of mortar fire hit the government-held suburb of Hrasnica, near Sarajevo's airport. Later at least four people were wounded when several artillery shells hit the Muslim suburb.
UN peace-keepers said Serbian commanders were 'incandescent with rage' after government troops attacked Serbian villages south-west of the Bosnian capital. And as the fighting continued around Bihac, seizure of ground from the Serbs sparked an exodus of thousands of Serbian refugees, with hundreds seeking refuge in Serb-held areas of Croatia.
Troops of the mostly Muslim government force crossed the Una River and swept into Bosanska Krupa, trapping several hundred Serbian soldiers, UN officials said. Bosanska Krupa, 130 miles north-west of Sarajevo, had a pre-war population of about 20,000. It would be by far the largest Serb-held town to fall to the government forces since the war began in April 1992. In theory, the UN has the right to respond to such problems by calling on Nato air power, but is unlikely to do so in spite of Friday's agreement between the UN and the alliance for a 'more robust' use of air strikes. But the UN's reluctance to call in the jets may be complicated by Washington's support for the Bihac offensive and its decision to circulate at the UN a resolution to lift the arms embargo on the Sarajevo government in six months' time.
In Sarajevo, hundreds of explosions and machine-gun bursts broke the uneasy calm imposed in February, when heavy weapons were banned from the city by a Nato ultimatum. UN monitors counted 74 detonations in three hours last night, but could not identify the weapons.
The UN noted troop movements in the area of Bosanska Krupa, which suggests the government forces are keen to defend the week's gains against a possible Serbian counter-attack. A State Department spokesman in Washington told reporters: 'We are understanding of their decision to exercise their right to defend themselves by force of arms.'
The Serbs are now trying to link the fuel issue to the Bihac attack and to a Bosnian withdrawal from the Igman DMZ. Bizarrely, they also have issued a demand that peace-keepers stop firing on their positions in northern Bosnia.
The UN has rejected any such linkage, but seems at a loss how to resolve its various problems.
UN officials visited Pale yesterday for talks with Bosnian Serb leaders in an attempt to secure the release of seven people in Serbian detention, and to win clearance for fuel convoys. A similar message was conveyed by a UN letter to Pale, but apparently had no effect.
There is growing concern for the safety of four British soldiers and their female interpreter, who spent a fifth day in prison in Kupres, while Serbian officials pondered their reasons for crossing into Serb-held territory on Tuesday. 'The Serbs have accused them of being spies,' Major Herve Gourmelon said. 'They claim the (Muslim) doctors are not doctors but spies.' The UN has hotly denied both claims.
'Our main priority is to get them out safely and as quickly as possible,' a UN spokesman said. The UN assured reporters that the British soldiers were in good condition, but then admitted officials had not been able to contact them.