U.S. Afghan buildup may involve brigade per quarter

By Adam Entous

WASHINGTON (Reuters) - The Pentagon envisages carrying out President Barack Obama's anticipated troop buildup in Afghanistan gradually at a pace of about one brigade per quarter, U.S. officials said on Tuesday.

The first large-scale brigade under the expected buildup, accompanied by support units, could arrive before spring, when fighting typically picks up. A top priority for Pentagon war planners is reinforcing troops in southern Afghanistan around Kandahar, a key Taliban stronghold.

But officials, speaking on condition of anonymity, said Afghanistan's crumbling infrastructure would make it difficult for the Pentagon to field and equip more than a single brigade every three months, or approximately four a year.

That means a large buildup of forces in Afghanistan could stretch well into 2011, depending on how many additional troops Obama decides to send and what types of units get deployment orders, officials briefed on the deliberations said.

Pentagon Press Secretary Geoff Morrell declined to comment on specific troop levels but said of any prospective buildup: "This will not be done overnight... This is going to take some time to deploy additional forces to Afghanistan, if that is the route we take."

Brigades range in size but generally include 3,500 to 4,000 troops. They can swell to over 5,000 troops if other support units are attached to them. Marine brigades can be larger.

Key members of Obama's national security cabinet, including Defense Secretary Robert Gates, favor a gradual U.S. increase of 30,000-plus troops, officials said. The deployment of thousands of additional U.S. trainers could boost that number to 35,000 or more, but estimates vary widely.

Other White House advisers have been pushing behind the scenes to keep the number closer to the 20,000-range with a focus on training Afghan security forces, officials said.