Updated

The Pentagon is unsure how long it can sustain the current pace of National Guard (search) and Reserve deployments to Iraq and Afghanistan, a senior official said Thursday.

"If we stress (the reservists) too much and have too many multiple call-ups, we're going to reach a point to where you would break," said Thomas Hall, the assistant secretary of defense for reserve affairs.

"We're all looking at and trying to" determine where that point is, he added, "while at the same time hoping the world situation will change" and allow a reduction in U.S. forces in Iraq.

"But you sort of have to plan (as if) we had to continue at the present rate," Hall said. "Would that break us, or not? We believe we can sustain that. But could you sustain that for 10 years or 20 years or 30 years?"

Guard and Reserve soldiers currently account for about half of the 155,000 U.S. troops in Iraq (search), although Hall said plans call for reducing that substantially over the coming year or two.

In what some believe is a foreshadowing of deeper problems, the Army Guard and Reserve have been falling short of their recruiting goals in recent months. Hall, however, said he has been assured by the Guard and Reserve chiefs that over the course of the year they will reach their targets with the help of 2,400 extra recruiters and large new signup bonuses.

In testimony before the Senate Armed Services Committee, Gen. Richard Myers (search), chairman of the Joint Chiefs of Staff, noted "we're having some problem" in recruiting for the Guard and Reserve.

"I don't think we're at the point where this is a grave concern yet," Myers said. "It's just something we need to watch, as we go through this year."

Hall said there is no plan currently under consideration by him or Defense Secretary Donald H. Rumsfeld to change the current policy of limiting Guard and Reserve mobilizations to 24 months. Under that policy, for example, if a Guardsman was called to active duty for six months following the Sept. 11, 2001, terrorist attacks to beef up security at a federal installation, and then was mobilized for 18 months for the Iraq war, he could not be called up a third time.

Technically, the Pentagon has presidential authority to mobilize the Guard and Reserve an unlimited number of times for Iraq or Afghanistan, so long as each mobilization is no longer than 24 consecutive months. Hall said Rumsfeld believes it would be unfair to the Guard and Reserve members, as well as their families and employers, to make them do more than 24 cumulative months.