LONDON – US war commander General David Petraeus will leave his post as chief of US and Nato forces in Afghanistan before the end of the year, the Times newspaper reported Wednesday.

US President Barack Obama plans to replace Petraeus, who was only appointed eight months ago, as part of a broad reorganisation of senior US officials in Afghanistan, according to the British paper.

"General Petraeus is doing a brilliant job but he's been going virtually non-stop since 9/11 (and) he can't do it for ever," Geoff Morrell, the Pentagon press secretary, told the newspaper.

"This is a heck of a demanding job, he will have to be rotated out at some point," he added.