Afghanistan's ousted Taliban are "terrorists" fighting a losing battle, former US first lady Senator Hillary Rodham Clinton said Thursday during a brief visit to Afghanistan.

"The message should go out that the Taliban terrorists are fighting a losing battle," she told reporters after meeting with President Hamid Karzai at the presidential palace in Kabul.

"They cannot win because they cannot intimidate and undermine the resolve of the Afghan people to have a future free of this kind of terrorism," said Clinton, who is spending Thanksgiving with troops hunting remnants of the hardline militia.

After meeting with Karzai and Finance Minister Ashraf Ghani, Clinton said: "I'm very impressed by the resolve of the Afghan government and President Karzai in particular, and the United States is as resolved to stand as a strong partner to ensure that the terrorists, whoever they are and wherever they come from, will be dealt with.

"I think that there's not only the resolve but there will be the resources and forces necessary," she said.

Rhode Island Senator Jack Reed, who accompanied Clinton, warned that the United States had to be committed to a long struggle in Afghanistan, where Taliban militants continue to launch regular attacks on US and Afghan troops and aid workers two years after the regime was toppled.

"Our biggest error would be to assume that this battle is over. This battle continues and we have to commit ourselves to a very long struggle," Reed said.

"We have to signal not just by words but by deeds that we're committed to the people of Afghanistan not just this month or next month but for a very long time," he said.

The Democrat senators, both members of the Senate Armed Services Committee, are on an official visit to Afghanistan and Iraq.

Karzai said they had discussed "various aspects of Afghan life," with Clinton taking a particular interest in maternity care. Afghanistan has among the world's highest infant and maternal mortality rates.

Clinton said she also met with representatives of women's organisations who raised concerns about the rights of women in the draft constitution, which is to be debated and approved next month.

"I understand their concerns and I'm confident that they will be raised and dealt with," she said.

The new constitution should "embody in a document the hopes and aspirations of the Afghan people, all of them, men and women" and establish institutions "to guarantee a better future for the children of Afghanistan", Clinton said.

Clinton and Reed had Thanksgiving dinner with US 10th Mountain Division troops at Bagram Air Base north of Kabul.

She said her visit was "to tell them they're doing a great job and we're very grateful to them."

The senators then headed south to the former Taliban stronghold of Kandahar to meet with troops there.

Clinton's visit follows a fatal helicopter crash on Sunday near Bagram which killed five US troops and injured seven others.

The troops were en route to northeast Afghanistan where 10th Mountain Division soldiers are taking part in a major operation to hunt Taliban fighters and their allies.

Militants have also increasingly targeted aid workers. In the most recent deadly attack, French UN worker Bettina Goislard was shot dead on November 15 by suspected Taliban in Ghazni town southwest of Kabul.AFP