Osama Bin Laden has claimed responsibility for the failed attack on a US airliner on December 25 in a new audio tape.
In the tape obtained by Al Jazeera, the world's most wanted man warns Barack Obama, the US president, that there will be more attacks unless he finds a solution to the Palestinian crisis.
The audio tape is believed to have been recorded last month.
"The message I want to convey to you through the plane of the hero Omar Farouk [Abdulmutallab], reaffirms a previous message that the heroes of 9/11 conveyed to you.
"America will never dream of living in peace unless we live it in Palestine. It is unfair that you enjoy a safe life while our brothers in Gaza suffer greatly.
"Therefore, with God's will, our attacks on you will continue as long as you continue to support Israel," bin Laden said.
Al-Qaeda's leader concluded: "If it was possible to carry our messages to you by words we wouldn't have carried them to you by planes."
'Sense of timing'
Phil Rees, the author of Dining with Terrorists, told Al Jazeera: "Bin Laden has a great sense of timing; it's a complete poke in the eye to President Obama at a time when Obama is domestically suffering.
"One thing is very clear, Osama still has followers spread all over the world and such messages do reinvigorate the spirit in these people about their mission"
Imtiaz Gul, chairman of the Centre for Research and Security Studies
"The reference to Palestine is possibly the most interesting part of this because he almost now becomes the al-Qaeda leader that speaks about Palestine.
"What you've now got in Gaza is bin Laden looking at the situation where there's a peace process which is going nowhere, and in an ironic way, Hamas is at the frontline of the battle with al-Qaeda there."
Abdulmutallab, who is now in US police custody, allegedly attempted to ignite explosives sewn into his underwear as Northwest Airlines Flight 253 made its final descent to Detroit on Christmas Day.
He had boarded the flight in Amsterdam, but purchased his tickets in Ghana on December 16.
Passengers on the flight were able to overpower the would-be bomber as he attempted to ignite the explosive's fuse.
After being taken into custody, Abdulmuttalab told police he had been directed by al-Qaeda and had obtained his explosive device in Yemen.
Al-Qaeda in the Arabian Peninsula, the organisation's affiliate in Yemen, has also claimed responsibility for the attack, describing it as a revenge for the US role in a Yemeni military offensive against al-Qaeda.
Obama has criticised his own intelligence agencies for failing to piece together information about the suspect which should have stopped him boarding the flight.
Imtiaz Gul, the chairman of the Centre for Research and Security Studies in Islamabad, told Al Jazeera that the al-Qaeda leader in his new message was likely designed to emphasisehis commitment to the cause of the Palestinians.
"Probably this was to remind the Palestinians of al-Qaeda's commitment to the cause and perhaps coinciding it with the first year of Obama's presidential office," he said.
"One thing is very clear, Osama still has followers spread all over the world and such messages do reinvigorate the spirit in these people about their mission.
"I think the validity of this tape should be subjected to scrutiny because we haven't heard from Mr Bin Laden for quite some time."
Osama Hamdan, a spokesman for the Palestinian Hamas movement, told Al Jazeera: "All Arabs and Muslims support our cause. [But] the Palestinian position is clear, the resistance is against the occupation, the Israeli army who is occupying and killing our people.
"Everyone knows that the policies of the US have created huge problems in the region. At this moment, we know who our enemy is - the Israeli occupation," he said.