By Ismail Sameem and Matt Robinson
KABUL (Reuters) - An elderly relative of Afghan President Hamid Karzai was shot dead by NATO forces during a botched night raid in southern Afghanistan Thursday, Karzai's brother said, stoking controversy over the war's civilian toll.
The mistaken killing of civilians by NATO troops is one of the most persistent sources of friction between Karzai and his Western backers, and was back in the spotlight this month after Washington offered a rare apology for the death of nine Afghan boys gunned down by helicopters while collecting firewood.
Yar Mohammad Khan, a cousin of President Karzai's father, was shot dead when he emerged from his house during a raid by foreign troops in Kandahar, said provincial council head Ahmad Wali Karzai, who is also the president's brother.
"While the operation was going on in the area, Khan walked out of his house and he was shot dead by mistake by ISAF forces outside his house," he told Reuters.
He said Khan's house, in the Dand district of Kandahar, was not the target of the raid.
NATO-led forces said in a statement they had killed the father of a Taliban leader during a night raid in Kandahar, after they spotted him holding an AK-47 automatic rifle.
A spokesman later said they were investigating the incident and the identity of the dead man, following reports he was a relative of Karzai, but declined to comment further.
Karzai's spokesman said the president -- who has long been a vocal critic of night raids -- knew the dead man personally, both as a relative and because they came from the same village.
"The president is sad to hear about another civilian casualty case, and has ordered an investigation," spokesman Waheed Omer told Reuters.
"He calls on ISAF (the NATO-led International Security Assistance Force) to protect civilians rather than killing them."
Karzai condemned the March 1 killing of nine Afghan boys during a NATO air assault in eastern Afghanistan, clouding a visit by U.S. Secretary of Defense Robert Gates this week to assess the ground before the start of a planned U.S. troop draw-down in July.
General David Petraeus has stepped up night raids dramatically since taking over command of U.S. and NATO forces in Afghanistan last year, despite criticism of the tactic from President Karzai and protests by ordinary Afghans.
Critics argue such raids only undermine Western efforts to win support from the population in the fight against an expanding insurgency.
Kandahar is the heartland of the Taliban and the focus of a Western military offensive to drive out insurgents and turn the tide of the almost decade-old war.
Last year was the most lethal for non-combatants since the ouster of the Taliban in 2001, with a 15 percent rise in civilian casualties to 2,777, the United Nations said in a report Wednesday.
Seventy-five percent were killed by insurgent attacks, but coalition forces are still responsible for a substantial number of deaths and the killings are often a flashpoint for both popular and government anger in the country.
(Editing by Sugita Katyal)