WASHINGTON — Pentagon leaders yesterday signaled a surge in U.S. forces in Afghanistan "sooner rather than later," a shift that could send some units there within weeks, as officials prepare to cut troop levels in Iraq.

Senior military officials are looking across the services to identify smaller units and other equipment that could be sent to Afghanistan, according to a defense official.

Although there are no brigade-sized units that can be deployed quickly into Afghanistan, military leaders believe they can find a number of smaller units such as aviation, engineering and surveillance troops that can be moved more swiftly, said the official, who requested anonymity because the discussions are private.

The moves are expected to happen within weeks rather than months, the official said.

The change in planning comes amid growing violence in southern and eastern Afghanistan, prompting U.S. commanders overseeing operations in the country as well as other military brass to push the Pentagon's Joint Chiefs of Staff to re-evaluate troop rotations to Iraq and Afghanistan.

On Sunday, nine U.S. soldiers, including 1st Lt. Jonathan P. Brostrom, 24, of 'Aiea, were killed at a remote outpost in eastern Afghanistan during a sophisticated offensive by hundreds of insurgent fighters, the largest single American loss of life in Afghanistan in three years.

Military leaders are weighing requests from commanders in Afghanistan for more troops, aircraft and other assistance. And they are trying to determine the right balance between the needs of the force in Iraq, versus troops in Afghanistan who are facing a Taliban resurgence.

To date, the fight in Afghanistan has taken a back seat to Iraq, which has been the strategic priority. While Iraq remains the top goal, it now appears the military believes there should be a more urgent emphasis on Afghanistan than there has been.

Faced with an increasingly sophisticated insurgency, particularly along Afghanistan's border with Pakistan, Defense Secretary Robert Gates said yesterday that sending more troops would have a significant impact on the violence.

"I think that we are clearly working very hard to see if there are opportunities to send additional forces sooner rather than later," Gates told Pentagon reporters. But, he added that no final decisions or recommendations have been made.

His comments suggested an acceleration in what had been plans to shift forces there early next year. And they came as the political discourse on Afghanistan as a key military priority escalated on both Capitol Hill and the presidential campaign trail.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, who recently returned from meetings with commanders in Afghanistan, said they clearly want more troops now.

"It's a tougher fight, it's a more complex fight, and they need more troops to have the long-term impact that we all want to have there," said Mullen, who also met last week with Pakistani leaders.

There are currently 36,000 U.S. troops in Afghanistan, including 17,500 with the NATO-led force, and 18,500 who are fighting insurgents and training Afghan forces.

The Associated Press and Los Angeles Times contributed to this report.