Montenegro, the pro-western partner to Serbia in the Yugoslav federation, is poised to launch its own currency, setting itself on a collision course with its larger republic that may see a new round of Balkan fighting.
Notes for the new currency, the Marka, are already being printed in heavily guarded presses, and Montenegro's President, Mr Milo Dukanovic, says they could be ready for distribution "within days".
His move comes with the failure of talks last week between Serbs and Montenegrins on demands by the latter for greater self-government in their federation.
With Yugoslavia in economic chaos following the war with NATO and western sanctions, its own currency, the dinar, has lost a third of its value in just a month. Montenegro, by contrast, is being assisted by US aid, with more than $10 million sent into its coffers in the past year.
The currency plan was designed by a US economics professor, Dr Steve Hanke of Baltimore University, and would see the Marka linked to reserves of the German Mark. Diplomatic sources say the US wants to see Montenegro succeed, to show Serbs what they too can achieve, in terms of international backing, if they jettison the Yugoslav president, Mr Slobodan Milosevic.
Dr Hanke said the stability created by the Marka can suck Serbian businesses into Montenegro. "I anticipate that a lot of firms will consider relocation," he said.
But it is the relocation of Yugoslav army units to Montenegro that worries many.
In August, when Mr Dukanovic called for a referendum on independence, Yugoslav troops were deployed on the streets of the leafy capital, Podgorica, where they faced-off against lightly armed local police units.
At the time, the US advised President Dukanovic not to press ahead with the referendum, fearing a war. Now, the US stance appears to have hardened, with Dukanovic making his currency announcement after consultations with the US Secretary of State, Ms Madeleine Albright.
The Prime Minister of Yugoslavia, Mr Momir Bulatovic, warned this weekend that he would not allow any loosening of tied by Montenegro, saying: "Yugoslavia's leadership and President Slobodan Milosevic are determined to protect the state's interest at any cost."
In 10 years, Yugoslavia has seen four of its republics - Bosnia, Croatia, Macedonia and Slovenia - break away and the province of Kosovo left in limbo. The economy has collapsed and foreign reserves are now exhausted, and groups ranging from soldiers to pensioners have taken to the streets protesting at the lack of payments.
Losing Montenegro, its only link to the sea, would be a further blow and one Milosevic is likely to resist. Yet Montenegro, with 650,000 people, has little to pit against the national army, controlled by Serb officers.
While currency notes will this week be distributed around Montenegro, Mr Dukanovic has so far made no final decision about issuing them. He may be using the threat to get better terms from Serbs after failed talks last week in Belgrade.
But if the move triggers fighting, it is far from clear that anyone will come to the help of Montenegro, many of whose 650,000 people are themselves Serbs. It may be significant that Dr Hanke, happy to take the credit for the Marka scheme, gave interviews on its likely success not in Montenegro, but from his new location: South America.