So far the outflow includes only about 325 Libyans, according to Ms. Pandya.

Part of the reason for anxiety in nations like Italy and Greece, which are most exposed to migrants from North Africa, is that the crisis is unfolding at a time when they say they can little afford a large-scale influx. Both Italy and Greece are struggling with huge debts and faltering economies, and Defense Minister Ignazio La Russa of Italy has warned Europe to prepare for migrations on a “biblical scale” as a result of the unrest.

Along with Italy, France, Spain, Malta and Cyprus have asked for a special E.U. fund to help them bear the brunt of the wave and assurances that other countries would share the burden of accommodating refugees. But no formal decisions had been made as discussions continued into the evening on Thursday.

The situation in North Africa also has sharpened the view within the Union that now that is not the right moment to allow Bulgaria and Romania to be external borders of the Union. The situation also has added urgency to efforts at pushing Turkey to control the border with Greece to prevent an influx of migrants.

At the meeting Thursday, Ms. Malmstrom presented a range of possible measures, including expanding operations by Frontex, the E.U. border security agency. She also said it was possible to unblock money from two funds to assist refugees and help E.U. member countries manage migratory flows.

Ms. Malmstrom also told ministers that the Union had a law on its books that could be used to accommodate and relocate people across the bloc who were fleeing conflicts. Those measures, if applied, would last for one year, extendable by a further six months, before those people would need to return to their countries of origin.

Meanwhile, human rights organizations called on the European Union to help provide refuge and assist evacuation programs.

Tom Porteous, director of the British office of Human Rights Watch, said Thursday that Europeans, in focusing on evacuating their nationals, seemed indifferent to the fate of those foreign workers who could not return home so easily or those who feared for their lives.