Sun May 4, 6:23 PM ET
Karzai survived the April 27 attack on a military parade, but three other Afghans were killed, including a parliamentarian.
"The angle that Al-Qaeda had a role in that is very clear," intelligence chief Amrullah Saleh told reporters.
The attackers were assisted by two government employees, one of them a weapons expert, Defence Minister Abdul Rahim Wardak told the same press conference.
"There are two people -- one of them working in interior ministry and the other in defence ministry -- who cooperated with them and have been arrested," he said.
The "mastermind" of the attack was also involved in the January storming of a five-star hotel in Kabul, Saleh said. That strike left eight people dead, including at least three foreign nationals.
The man, identified as Homayun, was killed in a raid by security forces on his Kabul hideout last week.
Another militant, a woman and a child were also killed in the operation on Wednesday, in which rebels shot dead three Afghan intelligence agents. Saleh said the woman was a would-be suicide attacker.
The operation had neutralised the cell, which had been involved in a series of suicide attacks, car bombs and assassination attempts, and was linked to militants based in Miranshah in Pakistan, the intelligence chief said.
The Taliban said it was responsible for the April 27 attack on Karzai.
The attackers had holed themselves up in a hotel about 500 metres (yards) from where Karzai and Afghanistan's top leadership were seated with a host of foreign diplomats ahead of the parade.
The parliamentarian and a tribal chief were killed, while a boy died in return fire. Three rebels also died.
It was one of the most brazen attacks in an insurgency by the Taliban, who were forced out of government in a US-led invasion in late 2001 for harbouring Al-Qaeda -- which at the time had training camps here.
Copyright © 2008 Agence France Presse. All rights reserved. The information contained in the AFP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of Agence France Presse.