Some of the heaviest fighting since the Syrian uprising began last year forced the closure of Damascus’s international airport Thursday as communications throughout the country went dark after the government apparently shut down Internet access.

Intense combat around the capital and elsewhere underscored a sense of urgency conveyed by U.S. officials about the fate of up to 3 million internally displaced Syrians and refugees as cold weather sets in.

On the political front, officials in Washington indicated that the Obama administration was moving toward recognition of a newly formed opposition coalition as the legitimate representative of the Syrian people. The announcement could come as early as two weeks from now, when the Friends of Syria group holds a meeting in Morocco. Britain, France, Turkey and other nations have already recognized the new Syrian National Coalition.

But officials, speaking on the condition of anonymity to discuss internal policy deliberations, said they foresaw no imminent change in the Obama administration’s refusal to help arm the rebels fighting Syrian President Bashar al-Assad’s forces.

NATO foreign ministers meeting next week in Brussels are expected to approve a request by Turkey for Patriot missile batteries to defend against cross-
border Syrian fire, which has occurred on several occasions.

The Patriot systems, however, are “not designed to change the situation inside Syria,” a senior NATO official said, and would not be deployed in a mode that would allow them to be part of a no-fly zone to protect Syrian communities from government aircraft.

Military personnel from the United States, the Netherlands and Germany — the three NATO countries with Patriot capabilities — are in Turkey examining potential sites for what the official said would be no more than a handful of batteries. The Patriot systems will operate under NATO command.

As Assad’s forces tried to push rebel fighters back from roads around the Damascus airport, at least two of what are only a handful of commercial airlines flying to the Syrian capital announced that they were suspending operations there. Egypt Air said its regular flights to Damascus would stop “until further notice,” and Emirates airline canceled flights.

In an additional sign that the rebels may be gaining momentum, opposition forces have taken control of at least a half-dozen government bases in the past week. One group announced the capture of two more bases Thursday.

“It appears as though the opposition in Syria is now capable of holding ground and that they are better equipped and more able to bring the fight to the government forces,” Secretary of State Hillary Rodham Clinton said Thursday evening.

Administration officials said they are closely watching a meeting of the Syrian National Coalition taking place in Cairo. They said they had laid out several steps for the group to take before U.S. recognition would be granted.

Clinton said no decisions have been made, but “we consider them on an almost daily basis.”

Recognition is largely a psychological step, a senior administration official said, but could lead to symbolic actions, such as closing the Syrian Embassy in Washington and turning over the facilities to the opposition.

The coalition was formed this month after the United States withdrew its support for the Syrian National Council, an opposition umbrella group that the administration said had failed to draw up viable plans for a transition government or appeal to minority groups inside Syria that still support Assad.

Although the coalition has yet to draw representatives from the Kurdish community in eastern Syria — where Kurdish fighters have skirmished with the rebel military in recent days — Lebanese Druze leader Walid Jumblatt called on Syria’s Druze community Thursday to “settle their choice and join the rebels.”

The senior administration official said actions that will demonstrate to U.S. policymakers that the new opposition group can “walk and chew gum at the same time” would include the formation of a “fully operational technical committee” to coordinate humanitarian needs and set priorities, a leadership group that can do political outreach to other nations and another to begin writing a constitution.

“So far, the reports from Cairo are quite good,” the official said. The coalition’s humanitarian committee has made international presentations asking for additional food and medical aid, as well as urgent requests for winter supplies of clothing and heating elements for refugees and for displaced people inside Syria.

The pressing need for such supplies was outlined Thursday by U.S. Ambassador Robert Ford, who was withdrawn from Damascus last year, and international aid representatives at a forum organized by Washington-based International Relief and Development. About 1.2 million to 2.5 million Syrians have been internally displaced; more than 450,000 refugees are said to be sheltering in Turkey, Jordan, Lebanon and Iraq.

The United States is the single largest provider of internal assistance to Syria, with about $200 million in donations. Most of the money goes through international aid organizations, including the United Nations, whose international appeals for Syria this year remain half-
funded or less.

U.S. officials have said that an additional $50 million has been spent on nonlethal aid to the Syrian opposition, including satellite telephones and other communications equipment.

State Department spokeswoman Victoria Nuland said the equipment is being put to good use as “over the last day or so . . . the regime does appear to be resorting to cutting off all kinds of communication — cellular networks, land lines, as well as Internet service — across the country.”

Babak Dehghanpisheh in Beirut and Anne Gearan contributed to this report.