Dignitaries attend the funeral of assassinated former Afghan president Burhanuddin Rabbani last month[Reuters]

Afghanistan's intelligence agency says it has thwarted a plot to assassinate Afghan President Hamid Karzai after arresting a bodyguard and five people with alleged links to the Haqqani network and al-Qaeda.

The National Directorate of Security (NDS) on Wednesday told a news conference that the plotters had recruited one of Karzai's bodyguards in order to kill him.

"The Afghan intelligence agency has arrested a group of six people in connection with an assassination plot against the life of the president," Siddiq Siddiqui, interior ministry spokesman, said.

According to the NDS, those arrested were linked to the Haqqani network - one of three Taliban-allied armed groups fighting in Afghanistan.

The United States blamed the Haqqani network for recent attacks launched against the US embassy in Kabul.

The Taliban, opponents of Karzai's government and 140,000 foreign troops stationed in the country, were not available for comment.

String of assassinations

News of the alleged plot to kill Karzai follows a string of assassinations targeting key allies of the president.

On September 20, peace envoy Burhanuddin Rabbani was killed by a suicide bomber at his Kabul home, throwing into turmoil Karzai's strategy for trying to hold peace negotiations with the Taliban.

The Taliban have not claimed responsibility for the attack, but Afghan officials claim it was carried out by a Taliban unit based in Pakistan and have accused Pakistan of refusing to co-operate in the investigation into his death. Islamabad has denied the charge.

Karzai's powerful brother, Ahmad Wali Karzai, was killed by a security guard at his home in the southern city of Kandahar in July.

And senior presidential adviser Jan Mohammad was murdered less than a week later.

Karzai is currently on a visit to India, where he has signed a new strategic partnership deal with New Delhi while trying to reassure Pakistan about the alliance with its historic foe.