Hardline Islamic parties in Pakistan say an apology by a US magazine over a story about a desecration of the Koran is a crude bid to ease Muslim anger.
Newsweek said US interrogators at Guantanamo Bay flushed a copy of the Koran down a toilet. It now says it erred in reporting the story.
But White House spokesman Scott McClellan said the decision not to issue a full retraction was "puzzling".
At least 15 people died in riots following the article's publication.
Pakistan has said it wants Washington to investigate the allegations, published last week.
The foreign ministry in Islamabad said it would expect the US to share its findings with the Pakistani government.
As well as at least 15 deaths in Afghanistan, more than 100 people were injured in violent protests across the Muslim world, from Pakistan to Indonesia, after the article's publication.
'No meaning'
The head of Pakistan's conservative six-party Islamic alliance, Qazi Hussain Ahmed, told the BBC that Newsweek's clarification held no weight.
http://news.bbc.co.uk/2/hi/americas/4553015.stm