General David Petraeus, named as the new commander in Afghanistan, tried to reassure an anxious US Congress that NATO-led troops are making headway in the country, amid fraying public support for the war.
Petraeus, the United States' most revered military officer, told senators the coalition force "has achieved progress in several locations" this year but warned them to brace for a "tough fight" ahead against Taliban insurgents.
With lawmakers concerned over a rift between military and civilian leaders, Petraeus vowed to work closely with his civilian counterparts and also promised to review disputed rules restricting troops' use of firepower.
President Barack Obama nominated Petraeus to take the helm in Kabul after the dramatic sacking of General Stanley McChrystal as commander last week.
McChrystal was forced to step down over a bombshell magazine article that quoted him and his staff disparaging their civilian counterparts in the administration, including Obama himself, the US envoy to the region and the US ambassador.
Petraeus, speaking at a senate hearing on his nomination, said he would seek "to forge unity of effort" with diplomats and White House officials.
After the hearing, the Senate Armed Services Committee promptly approved Petraeus's nomination, clearing the way for a swift confirmation for a general who enjoys the backing of both parties.
Staffers said the Senate will vote at around noon Wednesday.
He recounted how during his time in Iraq, he worked "very closely" with the US ambassador in Baghdad and that he would do the same with the American ambassador in Kabul, Karl Eikenberry, as well as NATO and UN envoys.
McChrystal and Eikenberry had widely-publicized tense relations, sharply disagreeing last year over plans for a major troop "surge" in Afghanistan.
Despite troubling signs from Afghanistan and growing public doubts about the war, Petraeus insisted there had been "security gains" over the past year in Afghanistan, particularly in southern Helmand province.
But he warned that violence would likely rise as Islamist insurgents seek to test NATO's will, and that it would take "a number of years" before Afghan security forces would be ready to take over.
"My sense is that the tough fighting will continue; indeed, it may get more intense in the next few months," he said.
In written testimony to the panel, he described the security situation as "tenuous, with instability fueled by a resilient and still-confident insurgency."
With members of Congress worried about delays in a pivotal operation around Kandahar city, the Taliban's birthplace, Petraeus said political efforts were underway in the area to secure local support.
He said the military had launched "a high tempo of targeted special forces operations" around Kandahar in recent months, without offering details.
The four-star general, credited with turning around the war in Iraq, pledged to review how new rules for combat are being carried out, saying he was aware of complaints by troops who say their hands are sometimes tied.
"When our troopers and our Afghan partners are in a tough spot, it is a moral imperative that we use everything we have to make sure that they get out of it," the general said.
But he said the rules of engagement -- designed to lower the risk of civilian casualties -- are "fundamentally sound" and that he agreed with the former commander that it was crucial to prevent civilian deaths.
The hearing reflected deep disagreement among lawmakers over war policy, with Republicans renewing their criticism of a July 2011 deadline set by Obama to start a gradual drawdown of US troops.
Republican Senator Lindsey Graham blasted the administration over the mid-2011 target date, saying it sent the wrong message to the enemy and that the White House needed to clarify "what the hell we're going to do" in Afghanistan.
Obama's fellow Democrats meanwhile are worried about an open-ended war and are pushing for a strict commitment to the 2011 deadline.