Allen: U.S. troop drawdown from Afghanistan to begin 'very shortly'

Washington (CNN) -- The man in charge of the war in Afghanistan said Wednesday that about a quarter of the American troops there will begin coming home "very shortly."

Gen. John Allen, commander of the International Security Assistance Force (ISAF) said that 23,000 of the 88,000 U.S. troops currently in Afghanistan will be home by September 30, 2012.

The so-called Phase 2 drawdown is going to begin "very shortly," Allen told reporters at a Pentagon briefing.

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When the drawdown is complete, ISAF will still have 65,000 U.S. troops available, plus about 40,000 troops from other ISAF nations like the UK, Canada and Germany.

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Plus, Allen said, the Afghanistan army and police have been growing. "During the last 12 months the Afghan security forces have expanded from 276,000 to 340,000, and they'll reach their full surge strength ahead of the scheduled deadline," he said.

And some of them are highly-trained. "There is really a significant and really a very important growing capability in the Afghan forces of their special operators: you know, nine battalion-sized formations, kandaks, of commandos; 72 special forces A-Teams," Allen said.

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One question Allen couldn't answer is how long the remaining 65,000 U.S. troops will remain in Afghanistan after the Phase 2 drawdown. "There's no number out there right now," Allen said. "I owe that kind of analysis to my command -- chain of command -- and ultimately to the White House. And we're going to make that analysis in the aftermath of the fighting season."