KABUL/WASHINGTON (Reuters) -- The United States has said it will not halt air strikes in Afghanistan as demanded by President Hamid Karzai after civilian deaths, and it denied using burning phosphorus in the attacks.
The U.S. military acknowledged on May 9 that the air strikes in western Afghanistan last week that struck crowded homes in two villages in Farah Province had killed civilians. Karzai put the death toll at up to 130 people.
If confirmed, it would be the biggest such case of Western forces killing civilians since they invaded in 2001.
Chanting "Death to America!" hundreds of Kabul university students marched on May 10 to protest the killings.
"We're going to take a look at trying to make sure that we correct those things we can correct, but certainly to tie the hands of our commanders and say we're not going to conduct air strikes, it would be imprudent," White House national security adviser James Jones said on U.S. television.
Asked what reaction he expected from Karzai, Jones said: "I think he understands that we have to have the full complement of our offensive military power when we need it.... We can't fight with one hand tied behind our back."
But he said the United States would "redouble our efforts to make sure that innocent civilians are not killed."
The Taliban were "using civilians as shields", he said. "So we have to take a look at this, make sure that our commanders understand, you know, the subtleties of the situation, the complexity of it, and do the right thing."
Karzai made his demand last week during a visit to Washington in which he met President Barack Obama.
Army General David Petraeus, who as head of U.S. Central Command oversees military operations in Afghanistan, said on U.S. television he had named a U.S. brigadier general to look at the use of air strikes.
Petraeus said it was important to ensure "that our tactical actions don't undermine our strategic goals and objectives".
Nader Nadery, a member of Afghanistan's independent human rights commission, said doctors who had treated victims from the incident had reported strange burns they believed may have been caused by a chemical like white phosphorus.
He said they "had burns on bodies and face, and the doctors have said it was something not usual from a bomb explosion."
White phosphorus, which erupts in flame on contact with air and can stick to flesh causing severe burns, is legal on the battlefield to create light or smoke and is not banned by treaties that forbid using chemicals as weapons.
But its use in populated areas to "smoke out" enemy fighters has been a persistent source of controversy.
"There was no smoke or [illumination] used in Farah," U.S. military spokesman Colonel Greg Julian said. "I can't say whether the insurgents used it, but we certainly didn't."
Suicide bombers on motorbikes killed at least seven people on May 10 when they attacked a police convoy in Afghanistan's southern province of Helmand, the Interior Ministry said.
Despite reinforcements to foreign forces, violence has surged to its worst level in the past year, the bloodiest period since U.S.-led troops overthrew the Taliban government more than seven years ago.