UN military commanders met in the German city of Stuttgart yesterday to co-ordinate the proposed multinational operation to help refugees in Zaire.
Lieut Gen Maurice Baril of Canada said the meeting would continue through the weekend but he declined to say how many troops would be involved.
Thirty five countries and organisations attended the meeting.
Gen Baril estimated that there are between 100,000 and 500,000 displaced refugees in Zaire of whom approximately half would require help.
"The mandate we have is to open a corridor to those who really need it. We're not here to feed or transport them, but to open this corridor," he said.
In Washington, the National Security Adviser, Mr Anthony Lake, said US officials are watching the chaotic flow of refugees in Zaire "day by day" as they consider the mission to aid the central African country.
Asked when Washington would decide whether to join a possible multinational humanitarian mission to the embattled region, Mr Lake said, "I don't want to predict that.
"We look at it day by day, and thus far every day we have seen movements that are encouraging," he said. "This is a very difficult issue.
The US and Rwanda argue that most true Rwandan refugees who wanted to go home have done so, leaving behind those who might be called to account for the 1994 bloodletting in Rwanda that spurred the refugees' flight and claimed roughly 500,000 lives.
Among recent positive developments, Mr Lake cited the return to their home country in recent days of some 600,000 Rwandans who fled to Zaire in the midst of the "ethnic bloodbath two years ago.
At the same time, however, scores of thousands of people - Rwandans and possibly some displaced Zaireans - have begun moving en masse in the region, their destinations frequently unclear.
Zairean rebels stopped UN agencies entering a large swathe of eastern Zaire yesterday to search for thousands of lost people while efforts to despatch an intervention force to the region flagged still further.
Complete confusion reigned over the whereabouts and number" of hundreds of thousands of Rwandan Hutu refugees and homeless Zaireans with the UN refugee agency, UNHCR, openly contradicting itself.
Field officers said reports from the UNHCR's headquarters in Geneva, based on satellite imagery, were not borne out by facts on the ground.
"We have no confirmation, no reports, and no information about any refugees moving towards Goma from Sake or the other side of Sake. We know nothing about any supposed 50,000 refugees moving toward Goma," Mr Ray Wilkinson, UNHCR spokesman in Goma, told reporters.
Patrick Smyth adds from Brussels: Dublin's Green MEP, Ms Patricia McKenna, has deplored the proposed involvement of the Western European Union in the UN's Zaire operation.
Ms McKenna argues that the WEU is "not a benign force in relation to Central Africa" as "three of its most powerful members, France, Britain and Belgium, have been the main suppliers of arms to the Rwandan army and Hutu militias which carried out the genocide of 800,000 Tutsis".
. The Church of Ireland Bishops' Appeal has allocated £10,000 for relief of refugees caught up in the Zaire/Rwanda conflict. The money will be channelled through Christian Aid.