Donald Rumsfeld's memos are notorious in the Pentagon
US Defence Secretary Donald Rumsfeld has attempted to play down a leaked memo in which he appears to raise doubts about the success of the "war on terror".
The memo was sent to the Pentagon's senior civilian and military leaders last week but reports of its contents later appeared in the USA Today newspaper.
It says the record against al-Qaeda is mixed and it suggests the US does not have the right mechanisms to know whether it is capturing, killing or deterring more terrorists than are being recruited.
Mr Rumsfeld has hit back, saying the memo was merely meant to provoke new thinking in the defence department.
In the memo, dated 16 October, he said that many sensible, logical moves had been made "in the right direction" but so far there had been no "truly bold moves".
Mr Rumsfeld rejected media reports that he had said reconstruction of Iraq was "going to be a long hard slog".
"I mention that we can win Iraq... but the battle in Iraq and the battle in Afghanistan, it will be a slog, a long hard slog," he said.
"But the big question is the broader one about the global war on terror."
He said one of the tougher questions was "how many young people were being taught to go out as suicide bombers and kill people?"
"Elevating that issue I think forces people to think about it in the broadest possible context, which is why I did so," the defence secretary said.
The BBC's Nick Childs says Mr Rumsfeld's style of missives and more informal memos - known by staff as Rumsfeld Snowflakes - are notorious in the Pentagon.
Despite the defence secretary's protestations to the contrary, our correspondent adds, the memo's language does appear a lot starker than many of his, or President Bush's, more upbeat public statements on the war on terrorism.
Opposition Democrats have seized on the comments as evidence that the Bush administration has been less than candid up to now in its portrayal of the war on terror.
Democrat Senator Tom Daschle said Mr Rumsfeld's comments illustrated how concerned the Bush administration was about "the failure of their policies in Iraq so far".
"They acknowledge that they have not succeeded to date," he said.
"I think that what we all need, though, is a good yardstick, a measure by which we can judge progress and ultimately success."