KABUL: Re-elected Afghan President Hamid Karzai vowed on Tuesday to form an inclusive government after stern warnings from Western supporters he would have to work harder to root out corruption.

Afghan President Hamid Karzai waves as he waits to meet UN Secretary-General Ban Ki-moon in Kabul November 2, 2009. [Agencies]

Afghan election officials on Monday canceled a needless presidential run-off vote after Karzai's only rival, former foreign minister Abdullah Abdullah, withdrew citing serious concerns about the election.

Karzai's return removes at least one obstacle as US President Barack Obama weighs whether to send up to 40,000 more troops to Afghanistan, where violence this year reached its worst levels since the Taliban were in 2001.

Faced with stern warnings from Obama, British Prime Minister Gordon Brown and other Western leaders, Karzai vowed to form an inclusive government.

"My government will be for all Afghans and all those who want to work with me are most welcome," Karzai said in a nationally televised victory speech.

"There will be crucial changes in our future government. Now we are determined to use all our forces, by any means, to remove this stain (of corruption) from our soil," he said.

Taliban claim success

Afghanistan endured weeks of political uncertainty after the August 20 first round was marred by widespread fraud, much of it in favor of Karzai, a crisis deepened by a resurgent Taliban who had vowed to disrupt the vote.

The Taliban termed Karzai's return a farce and vowed to continue its fight to drive foreign forces out of Afghanistan.

The Islamist militants launched sporadic attacks in the first round and vowed to disrupt the run-off. They said their fighters had "paralyzed" the electoral process with their attacks, including an assault on a UN guest-house last week in which five foreign UN staff were killed.

"Even they were not spared in the UN guest house in the heart of Kabul," the Taliban said in a statement sent to Reuters.

Afghanistan's government-appointed Independent Election Commission (IEC) called off the vote on Monday, saying it wanted to spare the Afghan people the expense and security risk of a vote with just one candidate.

Obama congratulated Karzai, but told him in a telephone call on Monday he had to get serious in cracking down on corruption and better serving his people.

There are currently around 67,000 US troops and 42,000 allied troops in Afghanistan. A White House spokesman said a decision by Obama on troop levels was still weeks away.

While under a critical eye from the West, Karzai still has plenty of support, especially in the Pashtun-dominated south and east. Hundreds took to the streets in celebration in the western city of Herat on Monday.

Karzai has ruled since US-backed Afghan forces toppled the Taliban in 2001.

"The credibility of the Karzai government is not going to be simply decided by this election, it will now be decided by the actions the president takes over the coming days and weeks," said a Kabul-based Western official who asked not to be named.