GENEVA — The United Nations appealed Wednesday for $1.5 billion in new aid to handle the steadily worsening humanitarian crisis created by violence in Syria and predicted that the number of refugees fleeing the conflict would double to more than 1 million in the next six months.
The increased estimate was at least the fourth time the United Nations had revised its projections upward on refugees in the nearly two-year-old uprising against the Syrian president, Bashar Assad, which has turned into a civil war that has left at least 40,000 people dead and has threatened to destabilize the Middle East.
The revised figures came as Syrian antigovernment activists and state media in Syria reported new violence convulsing the capital, Damascus, and other areas. The state-run SANA news agency reported that military forces had attacked insurgent positions in and around Damascus, Idlib, Hama, and Daraa, and had seized arms and attacked “terrorists,’’ the government’s term for Assad’s armed opponents.
Also Wednesday, Lebanese officials reported that Syria’s interior minister, Mohamed al-Shaar, was in Beirut for emergency medical treatment of injuries suffered in a Dec. 12 attack by insurgents in Damascus. There was no confirmation from the Syrian government, which had denied earlier reports that al-Shaar had been wounded in that attack.
Meeting representatives of donor governments here in Geneva, UN agencies said they were seeking $1 billion to assist Syrian refugees in five neighboring countries and a further $519 million to provide emergency aid to 4 million people inside Syria during the same period — about 20 percent of the country’s population.
The Syrian crisis was also a dominant theme of a year-end news conference at the United Nations by Ban Ki-moon, the secretary-general, who said he planned to convene a donor conference next year to raise additional aid money.
Ban also thanked all the neighboring countries in the region that had absorbed Syrian refugees and he called upon Israel publicly for the first time to accept them as well. There was no immediate comment from Israel, which remains in a technical state of war with Syria.
Ban reiterated his plea for an end to the violence in Syria and said ‘‘we’re doing our best to provide necessary humanitarian assistance. We are raising our voices, appealing to the international community.’’
Panos Moumtzis, the UN regional coordinator for Syrian refugees, said in a statement from Geneva that the enormity of the crisis ‘‘requires urgent support from governments, businesses, and private individuals. Unless these funds come quickly we will not be able to fully respond to the lifesaving needs of civilians who flee Syria every hour of the day — many in a truly desperate condition.’’
More than 525,000 Syrians have now registered as refugees, the UN refugee agency reported, about double the number it had recorded in early September. These include about 160,000 in Lebanon, 150,000 in Jordan, 140,000 in Turkey, and more than 65,000 in Iraq. The agency also included Egypt for the first time as a sanctuary for fleeing Syrians, reporting more than 10,000 had registered there.
The refugee agency now expects the number to double again during the next six months, Moumtzis said.
He based that forecast on present trends in the conflict, with 2,000 to 3,000 Syrians crossing into neighboring countries every day. Under a worst-case outcome, in which the conflict results in a massive exodus of civilians, the number of refugees could rise to 1.85 million, he said.
As it is, ‘‘the violence in Syria is raging across the country, there are nearly no more safe areas where people can flee,’’ Radhouane Nouicer, the coordinator of UN humanitarian aid based in Damascus, told journalists in Geneva, citing daily shelling and bombings in the suburbs of the capital.
The needs of Syria’s increasingly desperate population, facing winter cold and shortages of basics like food, were much greater than the aid sought by the United Nations, Nouicer said, but the appeal was ‘‘realistic assessment of what we can achieve’’ in the complex and dangerous conditions prevailing in the country.