Bush makes surprise visit to Afghanistan

George Bush made a surprise visit to Afghanistan on Wednesday, flying in secretly to support the country's fledging government in the face of rising violence from al-Qaida and Taliban militants.

The US president made a detour from a trip to India and Pakistan for a five-hour visit in Afghanistan that was not announced officially until Air Force One landed at the sprawling Bagram military base north of Kabul, the capital.

The White House wanted to conceal Bush's presence to reduce the risk of any attempt on his life.

Bush, making his first visit to Afghanistan, was later greeted by President Hamid Karzai at his palace in Kabul. Bush was accompanied by his wife, Laura, and US Secretary of State Condoleezza Rice.

Bush and Karzai were to have lunch and hold a joint press conference, said an Afghan official, who was familiar with Karzai's schedule but did not want to be named because of the sensitivity of the issue.

Bush was also to preside over a ceremonial ribbon-cutting for the US Embassy, and to give a pep talk to troops at Bagram Air Base.

Security was tight in the Afghan capital, with helicopters flying overhead and US military Humvee jeeps patrolling the streets.

The US military leads a 21,000-strong coalition of international forces hunting Taliban and al-Qa'ida militants, mostly in the country's south and east.

Karzai is a close ally of Washington and took power after the ouster of the hardline Taliban regime by US-led forces in late 2001 for hosting al-Qaida leader Osama bin Laden.

More than 200 US personnel have died in the Afghan conflict in the past four years. Militants stepped up attacks last year, making it the most violent since the fall of the Taliban.

In Washington, the top US military intelligence official told the US Congress that violence in Afghanistan increased 20 per cent last year.

"We judge insurgents now represent a greater threat to the expansion of Afghan government authority than at any point since late 2001, and will be active this spring," said Lt. Gen. Michael Maples, the head of the Defense Intelligence Agency.

There are about 19,000 US troops in Afghanistan, but that number will be reduced by about 16,000 this year.

It was Bush's second visit to a war front, following a secret trip he made to have Thanksgiving Dinner in 2003 with US troops in Iraq.

"We are confident in the security precautions that have been taken. One of those was not informing you of the trip until now," White House press secretary Scott McClellan said of the Afghan visit.

Despite intense manhunts and a multimillion dollar reward, bin Laden remains at large and is believed to be in hiding in the rugged border area between Afghanistan and Pakistan.

Bush and his wife Laura stepped off Air Force One under a bright, sunny sky against a background of snowcapped mountains. Secret Service agents were deployed around the plane with automatic weapons.

Bush was travelling to India later today and is heading to Pakistan later in the week.