Officials in Afghanistan say a former Taliban spokesman has been killed along with three other people.
Gunmen wearing Afghan army uniforms shot Mohammad Hanif at his residence in eastern Afghanistan. Hanif was arrested by Afghan authorities in 2007, and was released earlier this year.
In Kabul, crowds of angry Afghans threw stones at police and shouted anti-American slogans following accusations that NATO troops may have killed a civilian and wounded others.
Initial reports said the civilian was killed when troops fired on a vehicle, but NATO denied the charge.
Separately, British Foreign Secretary David Miliband says his country will consider any request from U.S. President-elect Barack Obama to send more British troops to Afghanistan.
In an interview appearing in the British newspaper "Daily Telegraph" on Friday, Miliband said British officials will look "hard" at any requests for help.
The British minister made a previously unannounced visit to Afghanistan this week and met with Afghan President Hamid Karzai.
Britain currently has 8,000 troops serving as part of a 50,000-strong NATO-led force in southern Afghanistan.
British officials say 128 of its soldiers have been killed in Afghanistan since 2001, when U.S. forces toppled a Taliban-led government.
Some information for this report was provided by AP and Reuters.