Bush held talks with President Hamid Karzai and other officials of the US-backed government that took power after the Taliban regime was overthrown for refusing to hand over leaders of the al Qaeda network responsible for September 11.

Security was tight for what was expected to be a five-hour visit to Kabul and Bagram, the main base for US troops in Afghanistan.

A group of low-flying helicopters carried Bush and his entourage from Bagram across the dusty plain over mud brick homes to Kabul, where he was received by Karzai.

Later at a joint press conference, Bush hailed Afghanistan's progress under President Hamid Karzai since the fall of the Taliban in 2001.

"We are impressed by the progress that your country is making Mr President, a lot of it has to do with your leadership," Bush told Karzai.

Karzai said that Afghanistan was indebted to the United States, which led the military operation that overthrew the hardline Taliban following the September 11, 2001 attacks on New York and Washington.

"We owe a great, great deal in this country's rebuilding peace, democracy -- strong steps towards the future -- to your support, to your leadership, to the American people," Karzai said.

Bush also said that he was confident Al-Qaeda chief Osama Bin Laden would be brought to justice.

"I am confident he will be brought to justice," he told reporters at the joint press conference with Afghan President Hamid Karzai when asked about the hunt for bin Laden.

"We have got US forces on the hunt for not only bin Laden but anybody who plots and plans with bin Laden," he said, adding that Afghan and Pakistani was also hunting the Al-Qaeda chief.

The US president was due to fly to India later as part of a tour that will also take him to Pakistan, another important ally in Bush's declared war on terrorism.

Bush is visiting Afghanistan at a time when the country is still troubled by a stubborn Taliban insurgency that has claimed 1,500 lives since the start of last year, including dozens of US soldiers.

US officials have portrayed Afghanistan as a relative success story compared to the US front in Iraq.

Millions of war refugees have returned to the country and presidential elections installed Karzai in October 2004 and the country's first democratically elected parliament in September.

But more than four years after US troops toppled the Taliban, al Qaeda leader Osama bin Laden and Taliban chief Mullah Mohammad Omar remain at large.

US Lieutenant General Michael Maples, director of the Defense Intelligence Agency, provided a stark assessment of the situation while speaking at a Senate hearing on Tuesday.

He said that insurgents represented a greater threat to the expansion of Afghan government authority than at any point since the Taliban's overthrow in late 2001.

He said the Taliban-dominated insurgency remained "capable and resilient" and would be active in the coming spring, having been emboldened by perceived tactical successes.