He said the United States can exert the most leverage when it is signing the checks.

"The place for us to start is to deal with corruption that may be associated with contracts we're letting or work that we're having done and development projects that we are undertaking in partnership with others including with the Afghans," Gates said.

Gates spoke to reporters at the historic military fort carved into Halifax's Citadel Hill, just before the start of the first Halifax International Security Forum, which is exploring a broad range of issues from Afghanistan and China to the Arctic and port security.

Afghan President Hamid Karzai has promised to do more to head off corruption that outside analysts say is rampant. But the newly reelected leader has also chafed under international criticism of corruption in his government. He has pointed out that the flood of development cash into his country over the last eight years has promoted some of the graft.

Standing with Canadian Defense Minister Peter MacKay, Gates said the U.S. military was planning for the eventual withdrawal of Canadian and Dutch troops, set for 2011 and 2010, respectively.

"I think it is sustainable," he said, adding that the top U.S. commander in Afghanistan, Gen. Stanley McChrystal, "is planning appropriately."

President Obama is expected to announce an increase of thousands more U.S. troops to Afghanistan in the coming weeks. U.S. leaders have stressed the need for other nations to boost their commitments as well.

But NATO and some allies, including Germany, have said they will wait to make any decisions until after the United States has made its announcement. The United States has a force of more than 68,000 in Afghanistan.

Also yesterday, House Republicans told Obama that his decision on Afghanistan troop levels was "long overdue" and that he should approve the request by his top commander there for about 40,000 more troops.

"For over two months you have been engaged in a strategy review that has left the country, our military and allies uncertain about your commitment to the war in Afghanistan and unsure about your will to do what is necessary to win this conflict," said a letter to Obama released by 14 Republicans, including Minority Leader John A. Boehner of Ohio.

"It is long overdue for our military to be in the execution stage" rather than the "evaluation phase," the letter said. "We encourage you to adopt General McChrystal's recommendation and to provide him with the forces that will give us the highest chance for success with the lowest risk to the safety and security of our forces."

Afghan Suicide Blast Kills 16

A suicide bomber killed 16 people and wounded at least 23 yesterday in a busy city square in western Afghanistan, while near Kabul, a powerful former warlord narrowly escaped assassination, officials said.

The attacks came a day after Afghan President Hamid Karzai took the oath of office for a second term. Karzai said he had put national reconciliation with Taliban insurgents at the top of his agenda.

Lawmaker Abdul Rasul Sayyaf, a former Northern Alliance leader who has been accused by Human Rights Watch of war crimes, was in a convoy with his bodyguards when a bomb hidden in an irrigation canal beside

the road exploded in the Paghman district north

of the Afghan capital, district chief of police Abdul Razaq said.

One car in the convoy was destroyed, and Razaq

said five of Sayyaf's bodyguards were killed. Sayyaf was not injured.

In the suicide bombing earlier yesterday in western Afghanistan, a bomber on a motorcycle blew himself up about

55 yards from the Farah provincial governor's compound in a crowded square, Gov. Rohul

Amin said. The dead included two children

and a police officer.

- Associated Press