NATO forces in Afghanistan need more troops and equipment to fight the Taliban, the outgoing commander of the 40-nation force said Wednesday.

Gen. Dan McNeill was speaking just before handing over command of NATO's International Security Assistance Force (ISAF) to Gen. David McKiernan. Both men are with the U.S. army.

McNeill said he was leaving behind a much-strengthened NATO force, but one that still fell well short of the numbers required by U.S. counterinsurgency doctrine.

"It's an under-resourced force. That's been a constant theme since I've been here," he said.

There have been significant increases in U.S. and other international forces in Afghanistan while McNeill has been in command, with the number of foreign troops in the country surging from 36,000 in early 2007 to 51,000 today.

Over the same period, the Afghan army has doubled in size to about 57,000.

But McNeill said a more viable number of international and Afghan forces to defeat the Taliban and provide security to all parts of the country would be around 480,000 troops, a number he called "absurdly high."

Canada has 2,500 soldiers as part of the NATO force, most of them based in the southern province of Kandahar.

'We will lose lives': Karzai

At a ceremony in Kabul Wednesday to mark the change in command, Afghan President Hamid Karzai warned McKiernan that his job as McNeil's successor would not be easy.

"We will have a lot of days of working together," Karzai said. "We will lose lives, NATO soldiers will lose lives, Afghan soldiers, Afghan personnel will lose lives, but we must remain steadfast."

McKiernan said in a speech that a change in command didn't mean a change in approach on the ground.

"The mission must continue without missing a beat," he said. "Insurgents, foreign fighters, criminals and others who stand in the way of that mission will be dealt with."

While there have been fewer larger scale Taliban offensives in recent months, the number of suicide bombings and other attacks on convoys and patrols has increased, NATO says.

In the month of April 2008, NATO figures show a 50 per cent spike in militant attacks in eastern Afghanistan, which McNeill blamed on peace agreements in neighbouring Pakistan between that country's new government and Taliban forces in border areas. The insurgency in Afghanistan, he said, could last for years unless Pakistan shuts down safe havens where militants train and recruit.

"If there are going to be sanctuaries where these terrorists, these extremists, these insurgents can train, can recruit, can regenerate, there's still going to be a challenge there," McNeill said in an interview last week.

More than 8,000 people have been killed in violence related to the insurgency over the past year, the most since the invasion of Afghanistan in 2001.

With files from the Associated Press