WASHINGTON (AP) — President Barack Obama is nearing a decision to add tens of thousands more forces to Afghanistan, though not quite the 40,000 sought by his top general there, as Pentagon planners work to make room for the influx.

Administration officials told The Associated Press on Monday the deployment would most likely begin in January with a mission to stiffen the defense of 10 key cities and towns. An Army brigade that had been training for deployment to Iraq that month may be the vanguard. The brigade, based at Fort Drum in upstate New York, has been told it will not go to Iraq as planned but has been given no new mission yet.

White House spokesman Robert Gibbs, meanwhile, said the president would meet again on Wednesday with key members of his foreign policy and military team but was unlikely to announce final plans for Afghanistan until late this month, when he returns from an extended diplomatic trip to Asia.

Gibbs said the Pentagon is “working on additional recommendations” to present to Obama and that Obama has made no decision on troop numbers, or even on what the ratio should be between combat troops and trainers.

Military officials said Obama will have choices that include a phased addition of up to 40,000 forces over some six months or more next year, based on security conditions and the decisions of NATO allies.

Several officials who spoke on condition of anonymity because the decision has not been made also said Obama’s announcement will be much broader than the mathematics of troop numbers, which have dominated the U.S. debate.

Officials said a substantial increase in troops is all but inevitable, but the precise number is less important than the message that an expansion and refocus of U.S. commitment in Afghanistan would send.

It soon will be three months since Afghan commander Gen. Stanley McChrystal reported to Obama that the U.S. mission was headed for failure without the addition of about 40,000 troops.

The officials, who spoke on condition of anonymity because final plans have not been disclosed, dubbed the likely troop increase as “McChrystal Light” because it would fall short of his request. They also said addition small infusions of troops could be dispatched next spring and summer.

The more gradual buildup, the officials said, would allow time to construct needed housing and add equipment needed for transporting the expanded force.

Besides being sent to cities and towns, the new forces would be stationed to protect important roads and other key infrastructure.

Part of the debate leading to Obama’s decision has been whether to move toward a more robust counterinsurgency strategy by attempting to retake territory from the Taliban insurgency and holding that turf while Americans work to rebuild and improve services for the population.

By using the new troops to protect cities and towns, the administration appears to be moving toward a middle ground that would deny Taliban advances on urban districts with the intention of shoring up support for the government of President Hamid Karzai.

That in turn would allow the fight against the Taliban then to expand to remoter regions.With winter coming to Afghanistan’s towering mountains, fighting could taper off as movement becomes difficult along the border with Pakistan. The Taliban has used the winter lull to resupply and regroup in years past, and the U.S. and a NATO-led alliance of countries fighting in Afghanistan are planning how to best place reinforcements for heavy fighting.

• Steven R. Hurst