“They are all weak and incapable of protecting the Muslim ummah, even if it is their duty by their religion,” he said in his keynote address.
“If we care to honestly assess our situation, we must admit that we and our religion have become the subject of much vilification and defamation.”
The event which runs until Dec 21 is attended by delegates from about 20 countries including Turkish President Recep Tayyip Erdogan and Iranian President Hassan Rouhani.
In his speech, Mahathir said Muslims and Islam had been equated with terrorism and government failures, acts of irrationality and those unworthy of civilised behaviour.
Adding that Muslim countries are accused of authoritarianism and lacking concern for human rights, he said Muslims could accuse the non-Muslim world of being biased and unjust in their assessments.
“But we cannot deny the facts that there are fratricidal wars in several Muslim countries, that many are beholden to the powerful non-Muslim nations, that Muslims are running away from their own countries to seek refuge in non-Muslim countries,” he said.
He added that Muslims are largely dependent on non-Muslims for many of their needs, to the point where they are unable to equip themselves with the means to ward off attacks by others.
“We depend on our detractors to supply us,” he said, adding that this was a far cry from circumstances in the 15th century when Muslims made advancements in science and engineering, especially the manufacturing of goods.
“But not now.”
On Islamophobia, Mahathir said Muslims were prepared to die to protect Islam and their fellow Muslims, and that some in fact were dying.
“But we have done more damage to our religion by our disreputable acts of terror,” he added.
Under European colonisation, he said, Muslims had lost their countries.
“From this decline, they have not recovered, even after regaining their independence.”
If nothing changed, he said, Muslims would continue to be oppressed and their decline would deepen.
He also said that Muslims could no longer isolate themselves as society has changed.
“No country may remain peopled by 100% Muslims now,” he said. “Other religions, other values, other ways of life affect us even if they do not live among us.”