MANILA - US Secretary of State Hillary Clinton called on Afghan President Hamid Karzai Thursday to show he was trying to weed out corruption, warning graft was at the heart of his government's woes.

"We are looking for measures of accountability and transparency that will demonstrate a clear commitment to the kind of government and outcomes the people of Afghanistan deserve," Clinton told reporters while in Manila.

"The corruption issue goes to the heart of whether the people of Afghanistan feel that the government is on their side."

However Clinton declined to comment on US media reports that the US ambassador to Kabul had sent memos to Washington expressing deep concern over the deployment of more troops to the country because of the graft issue.

The classified cables reportedly detailed ambassador Karl Eikenberry's strong reservations against sending reinforcements until Karzai's government showed it could tackle the graft that has spurred the Taliban's resurgence.

The reports said this was one of the issues US President Barack Obama was considering as he plotted what course to pursue in tackling the Taliban's bloody insurgency.

"I continue to be loathe to share any of the advice that the president has received in the course of his review," Clinton said when asked about the reported cables.

Clinton was speaking to reporters at the start of a two-day visit to the Philippines, which is part of a broader regional trip centred on the Asia-Pacific Economic Cooperation summit in Singapore on the weekend.