Afghan President Hamid Karzai has asked for American bodyguards to help reinforce his security.

Until now Mr Karzai has been guarded solely by Afghans, most of them mujahideen fighters.

Mr Karzai commands no private militia

But the assassination of Afghan Vice President Haji Abdul Qadir earlier this month has raised concerns over Mr Karzai's safety.

A presidential spokesman said Mr Karzai still trusted his Afghan guards but felt professionally-trained Americans would add to his security.

"Our people are ordinary mujahideen, they are good fighters but not good bodyguards," the spokesman Fazel Akbar said.

The Americans will help train the local security staff and set up a proper security system and are expected to stay for three to six months.

But the BBC's Kate Clark in Kabul said Mr Karzai's spokesman was trying to play down the significance of having foreigners guarding the Afghan president.

In the past, unpopular leaders have brought in people from abroad to protect them.

Threat

Mr Karzai is a civilian and therefore has no armed troops of his own to protect him.

Attacks on the Afghan Government

July: Haji Abdul Qadir, vice-president and minister of public works, shot and killed April: Four civilians die in bomb attack aimed at Defence Minister Mohammad Fahim February: Civil Aviation Minister Abdul Rahman killed in controversial circumstances

His guards include men who protected the anti-Taleban leader Ahmad Shah Masood, who was assassinated last September.

They also include some guards from the last pro-communist government and members of the newly-formed Afghan National Army.

After the killing of Abdul Haji Qadir, shot to death outside his office, many people have feared for the life of Mr Karzai and his cabinet.

Mr Qadir was a powerful Pashtun leader - one of the few in the Afghan Government other than President Karzai.

There was also an attempt on the life of Defence Minister General Fahim and last February, the Afghan Civil Aviation Minister, Abdul Rahman, was killed at Kabul airport in controversial circumstances.