There was broad agreement at the conference, though, that the only enduring way to address the humanitarian crisis was to end the fighting in Syria between the forces of President Bashar al-Assad and a fragmented array of opposition groups, some of whom are also fighting one another.

Last year’s aid conference aimed for $7 billion but managed to raise only half that amount, prompting United Nations organizations to slash the food rations for Syrian refugees in Jordan, Lebanon and Turkey. Chancellor Angela Merkel of Germany, which took in one million refugees last year, said those cutbacks were a major reason so many desperate Syrians left refugee camps and headed for Europe.

The participants at this year’s conference were determined not to repeat that failure.

Last year’s surge of migrants was “a huge, loud, wake-up call for the people in Europe and beyond Europe,” said Werner Hoyer, the president of the European Investment Bank and a former deputy foreign minister of Germany. Providing aid now, he said, “is much more economic than to wait until everybody has reached Amsterdam or Copenhagen and needs health care and schooling there.”

The difficulties of finding a long-term solution to the conflict hung over the conference. Mr. Ban endorsed the decision by the United Nations mediator, Staffan de Mistura, to suspend the Geneva talks on Wednesday, only two days after they formally started. “We should not have talks only for the sake of talks,” Mr. Ban said. “The coming days should be used to get back to the table, not to secure more gains on the battlefield.”

Though Syrian government forces, supported by Russian airstrikes, are conducting a major military offensive, the International Committee of the Red Cross reported on Thursday that aid convoys had managed to reach Moadhamiyeh, one of 18 Syrian towns besieged by the government or by rebel forces. The Red Cross said the convoys delivered enough aid to feed more than 12,000 people for about three weeks.