KABUL - Afghanistan will form a new anti-corruption unit to investigate high-level graft after widespread criticism and demands from Washington for it to do more amid a wider regional strategy review.

The announcement comes a day after U.S. Secretary of State Hillary Clinton bluntly warned that President Hamid Karzai and his government must do better, saying Washington wanted to see tangible evidence of Kabul's fight against rampant corruption.

On Monday, three days before Karzai was due to be sworn in for another five-year term, the government said it would set up a new body to tackle corruption and other crime.

Afghanistan has made similar announcements in the past, although previous efforts have borne little fruit.

President Hamid Karzai ... has dedicated his five years to fighting corruption, Interior Minister Hanif Atmar, flanked by U.S. ambassador Karl Eikenberry and British ambassador Mark Sedwill, told reporters at a news briefing in Kabul on Monday.

The new anti-corruption unit, part of the Attorney General's department, would be formed to prosecute public corruption cases involving high-level officials and other major crimes, the Interior Ministry said later in a statement.

Ambassador Eikenberry said the issue needed to be taken seriously.

(Corruption) requires action. Words are cheap. Deeds are required, he said.

Attention has focused on the legitimacy of Karzai's new government after a fraud-marred election in August, with U.S. President Barack Obama still to decide on a new strategy for Afghanistan that might include sending up to 40,000 more troops.

RAMPANT CORRUPTION

Karzai fell out of favor with many in the West before the August 20 election, his government seen as riddled with corruption.

Karzai and Finance Minister Hazrat Omar Zakhilwal have railed at the increasingly trenchant criticism from the West since Karzai's re-election was confirmed earlier this month despite findings of widespread vote fraud.

Zakhilwal told Reuters in an interview at the weekend that Western countries must share the blame for corruption in Afghanistan. Karzai has accused Western donors of mismanaging the billions of dollars of foreign aid that prop up Afghanistan's war-battered economy.

Obama has said stabilizing Afghanistan was an important part of Washington's strategy against terrorist networks which he said remained the greatest threat to U.S. security.

Fighting graft is seen as critical in winning back Afghan support in the war against a resurgent Taliban.

Last week, it emerged Eikenberry had expressed deep concerns in memos to the president about sending in more troops until Karzai's government improved its performance.

A central question as Obama debates whether to send more troops is whether Karzai can be a credible partner.

Obama, facing dissent among his advisers, has been criticized at home for dithering on the Afghan war strategy, with political pressure rising to make a decision soon.

General Stanley McChrystal, the top U.S. and NATO commander in Afghanistan, has requested 40,000 more troops for the war and says the mission is at risk of failure without them.

Prosecutors in the new anti-graft unit would be trained by officials from the EU police mission in Afghanistan, as well as others from Britain and the United States. Training and vetting for the new prosecutors would include polygraph tests, the statement said.

A major crimes unit would also be established, as Clinton had said on Sunday must be done, which would refer major corruption and other criminal cases to the new anti-graft body.

British police and the FBI would help train officers in the new crimes unit, officials said.

(Additional reporting by Yara Bayoumy and Hamid Shalizi in KABUL, Caren Bohan in SHANGHAI and Chris Buckley in BEIJING; Writing by Paul Tait; Editing by David Fox)