General David Petraeus has played down hopes for a swift turnaround in Afghanistan after nine years of war and said he would consider tactical changes in the face of escalating violence.
His nomination cleared a key Senate committee in a unanimous vote that showed bipartisan support for President Barack Obama's new pick to command the war.
Mr Obama sacked the last commander, General Stanley McChrystal, for disparaging civilian leaders in a magazine report.
Full Senate confirmation of 57-year-old Gen Petraeus looked imminent.
Appearing before the Senate Armed Services Committee, Gen Petraeus promised greater civilian-military unity of effort to counter what he called an 'industrial strength insurgency'.
He planned to reassess restrictive rules of engagement that critics say put US units at unnecessary risk in an attempt to limit fallout on Afghan civilians.
Gen Petraeus told the committee that broader changes were also possible depending on a White House review of war strategy in December.
Gen Petraeus is credited with helping to turn the tide in Iraq.
Mr Obama is counting on him to do the same with Afghanistan.
But Gen Petraeus cautioned against assuming that what worked in Iraq would work in Afghanistan.
He said progress was slower than expected and the task of training Afghan security forces to take over from US troops remained a monumental challenge.
‘My sense is that the tough fighting will continue. Indeed, it may get more intense in the next few months,’ Gen Petraeus told the committee.
He called the war a ‘contest of wills’ in which the Taliban aimed to chip away Western resolve.
‘They can sense concern in various capitals around the world and of course they want to increase that concern,’ he said as anti-war activists in the hearing room waved signs that read ‘No More War’ and ‘New general, Old graveyard.’
Police escorted out some of the protestors.
Gen Petraeus said the Taliban have begun to feel pressure from the extra 30,000 troops that Mr Obama authorised in December but cautioned that the insurgency remained resilient.
While he called the current war plan ‘sound,’ Gen Petraeus also suggested it was not set in stone.
