Osama bin Laden criticised relief efforts in Pakistan and called for action against climate change in what appeared to be a new audio tape from the al-Qa'ida leader issued on Friday in an Islamist forum.
The audio message, entitled "Pauses with the Method of Relief Work", was about 11 minutes long and was broadcast with a video showing still images of Bin Laden and images of natural disasters, the Islamist website used by al-Qa'ida said.
The authenticity of the tape and its precise release date could not be immediately confirmed. However, bin Laden congratulates Muslims on the holy month of Ramadan, which started on 11 August and ended on 9 September.
He describes the fate of the Pakistani people following catastrophic floods, saying: "Millions of children are out in the open air, lacking basic elements of living, including drinking water, resulting in their bodies shedding liquids and subsequently their death."
Bin Laden also touches on global warming, the second time he is believed to have made climate change a prominent theme of one of his statements.
"The huge climate change is affecting our (Islamic) nation and is causing great catastrophes throughout the Islamic world," he says in the tape.
"It is not sufficient anymore to maintain the same relief efforts as previously, as it has become crucial to deliver tents, food and medicine."
Islamic charities, some with suspected ties to militant groups, were quicker than the Pakistani government to provide relief to flood victims.
Pakistani and US officials have repeatedly expressed concern that the Taliban and other militant groups could exploit the disarray to gain recruits.
Bin Laden urges a "huge transformation" in how relief work is executed, calling the number of victims of climate change much bigger than the victims of war.
He blames countries in the region for setting aside a "huge part" of their budgets to finance armies without having any impact on the Palestinian cause.
"Spending is nowhere in comparison to what is being spent on those armies," he says.
The message was bin Laden's first since March 25, when he threatened to execute any Americans taken prisoner by al-Qa'ida if accused 11 September mastermind Khalid Sheikh Mohammed was executed.
US soldiers and Afghan militia forces launched a large-scale assault on the Tora Bora mountains in 2001 after the 11 September attacks on the United States in pursuit of the Saudi-born bin Laden.
But he has never been found and is believed to be hiding in the mountainous border areas of Afghanistan and Pakistan.