Croatia was poised yesterday to throw thousands of troops into the battle of Bihac, determined that the Muslim enclave in north-west Bosnia, bordering Croatia, should not fall to Serb forces. President Franjo Tudjman's government, which sees the survival of Bihac as vital to Croatia's security, massed soldiers near Serb positions outside the enclave as Serb forces with tanks and artillery bombarded Bosnian government lines.
US State Department officials said it appeared that some elements of the Croatian army had already gone into action around Bihac. The official Croatian news agency, Hina, said troops had begun to donate blood in response to a government appeal.
Croatia cannot afford to let Bihac fall as this would strengthen the supply lines between the Bosnian Serbs and their Croatian Serb kinsmen who seized about 30 per cent of Croatia's territory in the war of 1991. The Bihac enclave lies astride important rail and road communications linking the Bosnian Serb stronghold of Banja Luka with the Croatian Serb capital of Knin.
The Croatian and Bosnian leaderships signed a military co-operation agreement last weekend, shortly after Bosnian Serb and Croatian Serb forces launched a combined offensive on Bihac. The Bosnian commander in Bihac, General Atif Dudakovic, issued an appeal on Croatian television on Tuesday night for immediate Croatian intervention in the battle, in which Serb forces have captured almost 40 square miles of land.
The involvement of Croatian troops and rebel Croatian Serbs in the Bihac fighting indicates how the Bosnian war is intimately related to the conflict in Croatia. It suggests that if the West came to the defence of Bihac, as it has promised to do in the case of the eastern Bosnian enclave of Gorazde, it could find itself entangled in a Serb-Croat war in Croatia.
That is an unappealing prospect for Western countries, which have told Croatia that they have no intention of fighting wars on its behalf. On the other hand, the fall of Bihac, following the collapse in the last two weeks of the Muslim enclaves of Srebrenica and Zepa, would represent a colossal and possibly fatal blow to the United Nations operation in Bosnia.
The most obvious solution from the West's point of view is for the Croatian armed forces to shoulder the burden of trying to rescue Bihac. But this carries the risk of igniting a more general Serb-Croat conflict, possibly drawing in the Serbian-led Yugoslav army and forcing the collapse of the UN missions in Bosnia and Croatia.
The Bosnian and Croatian Serbs have aligned themselves with a renegade Muslim politician and business tycoon, Fikret Abdic, who is based in the town of Velika Kladusa, in the north of the Bihac enclave. Mr Abdic yesterday proclaimed the area under his control to be a "Republic of Western Bosnia" and said it would be a "neutral entity" within the pre-war borders of Bosnia.
In September 1993, Mr Abdic took a similar step when he declared an "Autonomous Province of Western Bosnia" over about one-third of the Bihac enclave. Bosnian government forces forced the collapse of his breakaway province last year, but Mr Abdic has since bounced back.
About 180,000 people, almost all Muslims, have been trapped in the Bihac enclave since the Bosnian war broke out in April 1992. Surrounded on all sides by Serb forces, the enclave has managed to survive with the help of UN aid deliveries by road and airlifts of military supplies undertaken over Serb-held territory from Croatia's Adriatic coast.
The Bosnian government called a temporary halt to the airlifts in early June after Serb forces killed the Bosnian foreign minister by shooting down a helicopter that was transporting him over Croatian Serb territory. But UN officials said that the airlifts to Bihac had resumed on Tuesday night, when a supply plane flew in from Croatia to the Bosnian army's airfield near the town of Coralici.
The Croatian and Bosnian leaderships signed their military pact only days after Croatia's Foreign Minister, Mate Granic, completed an important trip to Iran. Catholic Croatia and Islamic Iran have good relations, founded on a common hostility towards the Orthodox Serbs and cemented by economic and military co-operation.