Obama faces tough sell with Afghan troop plan

US president Barack Obama's national security team heads to Congress on Wednesday to sell lawmakers on his dramatic escalation of the Afghan war, which his field commander said would make a "huge difference".

Rising combat deaths and military costs have sapped US public support for the eight-year-old war and Obama's 30,000-strong troop increase plan has prompted protests from left-leaning leaders of his Democratic Party ahead of next year's congressional elections.

Within hours of Obama's speech announcing the extra troops would arrive within months — delivered as Wednesday dawned in Afghanistan — top US and Nato commander General Stanley McChrystal set off on a battlefield tour to rally his forces.

Paraphrasing Winston Churchill in a rousing speech by videophone to his commanders, McChrystal called Obama's pledge of reinforcements "the end of the beginning" of the war.

He told his commanders the additional forces would at last give them the troops they need to speed up the training of Afghan security forces and protect towns and villages.

Training Afghan troops was now their "main effort", he said.

"At the end of the day, the success of this operation will be determined in the minds of the Afghan people," he said.

"It's not the number of people you kill; it's the number of people you convince. It's the number of people that don't get killed. It''s the number of houses that are not destroyed. It's the number of children that do get to go to school. And as we increase our force numbers, we also increase our force capability because we understand that better."

Asked later if Obama's pledge of troops was enough, he told reporters, "I think it is going to make a huge difference. I think we'll be in great shape."

Later on Wednesday, top Obama administration officials were due in Congress, where they can expect a grilling from Democrats dubious of escalating the war and Republicans suspicious of Obama's call for an 18-month timeline to begin withdrawing.

In his televised speech on Tuesday, Obama said the goal of raising US troop levels to nearly 1,00,000 was to step up the battle against the Taliban, secure key centres and train Afghan forces so they can take over, allowing for a US withdrawal. 

"We always wanted to take over the responsibility for the destiny of our nation," Afghan defence minister Gen. Abdul Rahim Wardak told reporters, adding that Obama's speech confirmed that the US wants to help them do that.

"We just asked the international community to equip us quickly, to train us quickly, so that we can fulfil our historic responsibility."

Allies were also expected to send more soldiers, with Obama saying "the common security of the world" was at stake.

But Esmatullah, a young construction worker on a Kabul street corner, was unimpressed. "Even if they bring the whole of America, they won't be able to stablise Afghanistan. Only Afghans understand our traditions, geography and way of life."

British prime minister Gordon Brown urged coalition countries to back Obama's plans. French president Nicolas Sarkozy welcomed the plans, but did not commit France to following suit. Poland said it might send 600 troops to boost its contingent of 2,000.

There was no initial word in the morning from President Hamid Karzai, who has had a fraught relationship with the Obama administration amid his re-election which involved widespread voter fraud.

But after meeting Karzai, McChrystal said the Afghan president backed the plan. "It was really positive. The president was very upbeat, very resolute."

Karzai is due to announce the makeup of his new government in coming days, and Washington says it is watching closely for signs he will combat corruption and appoint competent ministers.

Obama's pledge to start bringing US troops home in 2011, provided conditions on the ground allow it, may help him contain rebellion among Democrats but drew swift condemnation from Republicans, who argue setting withdrawal timelines emboldens the Taliban and undermines support for US-backed governments in Afghanistan and Pakistan.

Congressional committees scheduled hearings on Wednesday and Thursday to review Obama's revised strategy, estimated to cost $30 billion this fiscal year. Obama has the authority to send the soldiers but Congress must approve the cost.

US secretary of state Hillary Clinton, defence secretary Robert Gates and the chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, are scheduled to appear before Congress.

McChrystal, who had recommended sending 40,000 more troops, will testify next week.

Major US troop movements are likely to begin in January and all 30,000 should be in place by the end of August, far faster than planners had earlier suggested and in line with McChrystal's request for reinforcements before the summer fighting season.

Other NATO members are expected to commit between 5,000 and 7,000 additional troops, although some of them are already deployed as part of the alliance's 42,000-strong contingent.

Marking a major shift in US strategy, McChrystal said the "vast majority" of the new combat troops would be fielded in partnership with Afghan units, a counter-insurgency mentoring tactic he said had not been fully possible in the past because the Afghan army and police were too small.

In his speech, Obama also focused on Pakistan, saying a cancer had taken root in its border region with Afghanistan and promised US help to end it. Some officials in Islamabad fear the US surge in Afghanistan will further destabilise their country.

A suicide bomber blew himself up outside naval headquarters in the Pakistan capital on Wednesday, killing a guard and criticially wounding two people, the latest in a series of such attacks which have killed hundreds.