Al-Qaeda initially planned to fly hijacked jets into nuclear installations - rather than the World Trade Center and the Pentagon - according to an Arab journalist who says he interviewed two of the group's masterminds.

The Arabic television station al-Jazeera says it will broadcast on Thursday the interview in which Osama Bin Laden's aides describe in detail how they planned the 11 September attacks.

Capitol Hill - the "third target"

In an article published in several European newspapers, documentary-maker Yosri Fouda said Khalid Sheikh Mohammed and Ramzi Binalshibh told him they had decided against the attack on nuclear power plants "for the moment" because of fears it could "get out of control".

Both men are on the FBI's most wanted list and have a $25m bounty on their heads.

The FBI says Khalid Sheikh Mohammed is one of Bin Laden's key lieutenants, while Ramzi Binalshibh is said to have shared an apartment in Hamburg with Mohammed Atta, the alleged ringleader of the hijackers.

Department of Martyrs

Mr Fouda said he was taken to a hideout in Pakistan. He says was told by a man there that Bin Laden was alive and well, but was not shown any proof of this.

Bin Laden - reportedly told of date for the attacks on 6 September

Khalid Sheikh Mohammed told him he was head of the al-Qaeda military committee and Ramzi Binalshibh the co-ordinator of what they refer to as "Holy Tuesday".

Over the course of two days, Mr Fouda says, the men gave him an insight into how the terror group operates and how the 11 September attacks were planned.

Mohammed and Binalshibh alleged that:

• The decision to launch a "martyrdom operation inside America" was made by network's military committee in early 1999

• Atta was summoned to a meeting with key hijackers in Afghanistan that same year

• Hijackers were recruited from al-Qaeda's Department of Martyrs, which is still active

• Mr Binalshibh wanted to be one of the hijackers, but was refused a US visa

• A number of reconnaissance teams travelled to the US ahead of the hijackers

• Ramzi Binalshibh posed in e-mails as Atta's girlfriend in Germany when the two communicated through the internet

• The fourth hijacked plane was heading for Congress, not the White House, when passengers overpowered the attackers

• The codenames for the targets were university faculties: "town planning" for the WTC, "law" for Congress, "fine arts" for the Pentagon

• On 29 August, Atta gave the date for the attacks to Mr Binalshibh, who ordered active cells in Europe and the US to evacuate

• Bin Laden was told on 6 September

At the end of his two-day interview, Mr Fouda writes, he was instructed to leave the videotapes behind so the faces of Khalid Sheikh Mohammed and Ramzi Binalshibh could be blanked out.

Despite promises that they would be returned, the videos never turned up. But, the journalist says, he did eventually receive voice tapes of the interviews.

He concludes that there is evidence of "disruption" within the al-Qaeda leadership, and that Bin Laden is more likely dead than alive.