* Governor says 64 civilians killed by ground, air strikes
* U.N. report says civilian casualties up 20 pct in 2010
* NATO-led force casts doubt on reported death toll
(Adds ISAF comments, paragraphs 6-10)
By Rohullah Anwari
ASADABAD, Afghanistan, Feb 20 (Reuters) - More than 60 civilians, including women and children, were killed in four days of operations by NATO-led troops and Afghan forces in eastern Afghanistan, a provincial governor said on Sunday.
Governor Fazlullah Wahidi told Reuters that 64 civilians were killed by ground and air strikes in the Ghazi Abad district of eastern Kunar province.
An Afghan presidential palace statement said more than 50 civilians had been killed, based on information from religious leaders, local officials and security forces.
"President (Hamid) Karzai strongly condemned the air strikes by foreign troops," the statement said.
Civilian casualties in NATO-led military operations, often caused by air strikes and night raids, have long caused friction between the Afghan government and its Western backers.
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The NATO-led International Security Assistance Force (ISAF) cast doubt on the reported death toll, but said an investigation involving Afghan officials would begin on Monday.
Rear Admiral Greg Smith, the chief ISAF spokesman, said the inquiry would centre on a firefight that began in a rugged and remote area on Thursday night and lasted more than five hours.
Video from weapons systems did not indicate any civilians, or permanent settlements, were in the area, he told Reuters.
"We had clear intelligence they were planning a meeting, a massing of Taliban, in that area that evening," Smith said.
He said that those targeted scattered in small groups along ridgelines and down into a remote valley and that "high-probability" -- apparently insurgent -- targets had been hit.
Earlier ISAF statements said 36 armed insurgents were killed and that seven civilians may have been wounded in a separate incident.
Governor Wahidi said that of the 64 dead, 20 were women, 29 were children or young adults, and the other 15 were adult men.
Operations have been going on in Ghazi Abad since Feb. 16.
An earlier ISAF statement on Sunday said ISAF had engaged an unknown number of insurgents in two separate operations and attacked with small-arms fire and air strikes. The coalition also said earlier seven civilians may have been wounded.
Videos taken by Reuters television in a hospital in the provincial capital, Asadabad, showed two children being treated for leg wounds alongside two wounded women.
"There have been ongoing operations in different parts of Ghazi Abad for the last three days," said a man who identified himself as Ibrahim, a resident in Elgal village in Ghazi Abad.
He said "bombardments" had killed 12 men, about 30 children and 10 women. Another villager, Farhad, said 62 civilians had been killed.
Ghazi Abad has long been a restive area. Afghan and ISAF officials say insurgents launch attacks and then hide in the inaccessible valley in which Elgal nestles.
There have been several recent attacks on ISAF and Afghan convoys on a tiny road that snakes through Elgal.
Rules governing air strikes and night raids have been tightened significantly by NATO-led forces in the past two years, leading to a drop in civilian casualties.
A United Nations report late last year found that civilian casualties in Afghanistan rose 20 percent in the first 10 months of 2010 compared with 2009, with more than three-quarters killed or wounded by insurgents. [ID:nSGE6BK07D]
The report found there were 6,215 civilian casualties in the period, including 2,412 deaths. Those caused by Afghan and foreign "pro-government" forces accounted for 12 percent of the total, an 18 percent drop.
Other rights agencies have since documented similar figures. [ID:nSGE71804N] (Additional reporting by Hamid Shalizi in Kabul; writing by Emma Graham-Harrison; editing by Mark Heinrich)