US-led airstrikes in Afghanistan have killed dozens of civilians ahead of talks between Presidents Barack Obama and Hamid Karzai.

The Red Cross claims more than 100 civilians are feared to have been killed. They include a first aid volunteer for Afghanistan's Red Crescent, who died along with 13 members of his family.

Spokeswoman Jessica Barry said staff sent to the scene of the raids in Western Farah province had found houses destroyed and dozens of dead bodies, including women and children.

"There were women and there were children who were killed. It seemed they were trying to shelter in houses when they were hit," she said.

Provincial police chief Abdul Ghafar Watandar said the death toll could be even higher and accused the Taliban of using the civilians as human shields.

"The fighting was going on in another village, but the Taliban escaped to these two villages, where they used people as human shields," said police chief Watander.

"The air strikes killed about 120 civilians and destroyed 17 houses," he said, but stressed the death toll was imprecise.

If confirmed, the figures would make the incident the single deadliest for Afghan civilians since the campaign to topple the Taliban began in 2001.

President Karzai, who is in Washington for talks with President Obama, dispatched a joint US-Afghan delegation to investigate the incident.

US Secretary of State Hillary Clinton said she deeply regretted the civilan deaths.

She also announced Afghanistan and Pakistan will commit to a trade agreement to increase foreign investment in the two countries.