Timeline: The search for Bin Laden

Osama Bin Laden: Top of Washington's 'Most Wanted' list

Since the 11 September 2001 attacks, a number of video tapes, audio recordings, faxes and other statements have been attributed to Osama Bin Laden.

But although the US has hunted the al-Qaeda leader using satellite tracking systems and sophisticated spying systems, Bin Laden remains at large.

He is widely believed to be hiding in the remote tribal region along the Pakistan-Afghanistan border with his deputy, Ayman al-Zawahri.

APRIL 2006

In an audio tape attributed to Osama Bin Laden, the speaker cites the cutting of Western funding to the Hamas-led Palestinian government as proof of a "Zionist-crusader war against Islam".

Western involvement in the troubled Darfur region of Sudan is also criticised in the tape, aired by Arabic TV station al-Jazeera.

JANUARY 2006

After a silence of more than a year, al-Jazeera aired an audio tape which CIA analysts say was made by al-Qaeda leader Osama Bin Laden.

In it, the speaker said new attacks on the US were being planned, but offered a "long-term truce" to the Americans, an offer the US quickly rejected.

MARCH 2005

Pakistan's President Pervez Musharraf says Pakistani troops had their best chance of capturing Bin Laden from May-July 2004, after the army launched an offensive along the border with Afghanistan. But he says the trail has now gone cold.

In the US, President George W Bush makes a rare mention of Bin Laden, saying the US is "working day and night" to bring him to justice.

DECEMBER 2004

An audio tape attributed to Osama Bin Laden calls on Iraqis to boycott January's election.

The voice, whose identity cannot be confirmed, names the Jordanian-born Abu Musab al-Zarqawi as "emir" of al-Qaeda in Iraq.

OCTOBER 2004

A Bin Laden videotape surfaces just days before the US presidential election.

In the tape, aired on the Arabic television station al-Jazeera, Bin Laden says the reasons behind the 9/11 attacks are still present and he threatens fresh attacks on the US, whoever is elected.

It is Bin Laden's clearest claim of responsibility so far for the 2001 attacks.

In an embarrassment for the Pakistani president, al-Jazeera says the tape was delivered to its Islamabad bureau.

JANUARY 2004

Al-Jazeera releases an audio tape in which Bin Laden talks about the capture of Saddam Hussein and attacks Arab states for backing the US-led war on Iraq.

SEPTEMBER-OCTOBER 2003

In audio tapes aired by al-Jazeera television station, Bin Laden praises the 11 September hijackers and calls for new attacks on the US.

APRIL 2003

An audio recording said to be of Bin Laden, in which he calls for attacks on the governments of the Gulf states, is released by the Associated Press news agency.

MARCH 2003

Senior al-Qaeda leader Khalid Sheikh Mohammed is arrested in Pakistan. Investigators believe he kept in contact with Bin Laden through e-mails and hand-delivered messages.

FEBRUARY 2003

An audio tape purporting to be from Bin Laden calls for attacks on US and British targets if Iraq is attacked. The US-led invasion of Iraq takes place the following month.

NOVEMBER 2002

In a tape broadcast on Arabic TV station al-Jazeera, Bin Laden refers to attacks in Bali, Yemen and the Moscow theatre siege which had recently taken place.

SEPTEMBER 2002

An alleged planner of the 11 September attacks, Ramzi Binalshibh, is captured in the Pakistani city of Karachi.

APRIL 2002

Old clips of Bin Laden and some of his top aides are aired on al-Jazeera, along with footage of an 11 September hijacker reading what appears to be his suicide note.

DECEMBER 2001

US forces apparently intercept radio messages in which Bin Laden is directing troops from Afghanistan's mountainous region of Tora Bora, but the trail goes cold and US officials admit they have no information on the al-Qaeda leader's whereabouts.

Meanwhile, al-Jazeera television airs footage of Bin Laden in which he refers to the attacks.

NOVEMBER 2001

A letter said to be from Bin Laden calls on Muslims in Pakistan to stand up for Islam as the country supports the US-led campaign against Afghanistan.

OCTOBER 2001

Bin Laden warns in a statement - broadcast on al-Jazeera two hours after the US-led coalition begins military strikes against Afghanistan - that it will have no rest until the Middle East conflict is resolved and US military bases in the region are shut down.