Defense Secretary Robert Gates held out hope Friday that U.S. forces in Iraq could continue a steady decline next year if security keeps improving — leaving 100,000 by year end.

But he did not rule out a small uptick in U.S. troops in Afghanistan.

While Gates would not put a specific number on Iraq troop levels, he agreed a consistent reduction would leave 10 brigades — roughly 100,000 troops — soon after American voters go to the polls for the 2008 presidential elections.

There are currently 158,000 U.S. troops in Iraq. The first brigade that is not being replaced left this month.

Gates said the capacity of Iraqi forces to bear more of the security burden and the ability of the Iraqi government to run the country are the leading factors that will influence how quickly U.S. forces can leave.

"My hope has been that the circumstances on the ground will continue to improve in a way that would — when General (David) Petraeus and the chiefs and Central Command do their analysis in March — allow a continuation of the drawdowns at roughly the same pace as the first half of the year."

Gates also criticized Congress' choppy funding for the wars. He said while the Pentagon welcomed the recent appropriation, it is less money than needed.

He said no furlough notices for Defense Department employees will be issued, a possibility that loomed until Congress passed the spending bill. But Gates said that prospect will reappear in a few months unless Congress supplies more money.

He said the military may run out of money by spring. That "requires us to make short term plans and short terms solutions," he said.

"I hope we don't have to have a replay this spring," Gates said.

Paying for the wars in Iraq in Afghanistan in fits and starts undermines military planning and risks the gains made by American troops over the past year, he said during a Pentagon news conference.

Congress recently provided $70 billion for combat operations, only half of what the President requested.

On Iraq, Gates was cautiously optimistic about further troop reductions beyond those already planned, but he declined to attach a specific number to that projection.

"We obviously want to sustain the gains that we have already made," Gates said.

In September Gates raised the possibility that U.S. troop levels could be reduced to 100,000, if conditions in Iraq improved. At the time, he stressed that it was a hope, not a plan and that it would depend on how well the initial troop withdrawals go during the first half of the year.

On Friday Gates said it was a lapse on his part to give an absolute number. Circumstances on the ground and the judgment of Gen. Petraeus, the U.S. commander in Iraq, will dictate further reductions. Current plans call for reducing the current 20 combat brigades to 15 by next summer. Gates said that could be pared to 10 by the end of 2008 if violence in Iraq continues to ebb.

Asked about the possibility of political reforms in Iraq, Gates said the country's leaders "are committed to getting it done. We'll see if they get it done."

Gates has been pressing U.S. allies to send more forces to Afghanistan, where the United States carries the largest share of the load. No more than 7,500 additional troops are needed there, Gates said Friday, and nearly half of those would be used to train Afghan military units.

Asked if the U.S. will fill any of those troop requirements, he said the Pentagon will continue to look at it.

Gates, a former CIA director, took control of the Pentagon a year ago after the embattled Donald Rumsfeld stepped down. And under his watch the president ordered a military buildup to quell escalating violence in Baghdad, which has resulted in a slow, but steady decline in attacks and both military and civilian casualties.