The figures include the world's tallest standing Buddha, a 53-metre statue carved into a cliff face in the central town of Bamiyan.
In an edict published by the Taleban-run Bakhtar News Agency, Mullah Omar declared the statues were insulting to Islam and should be destroyed so they could never again be worshipped.
The figures include the world's tallest standing Buddha, a 53-metre statue carved into a cliff face in the central town of Bamiyan.
There has been an international outcry over reports that priceless monuments and works of art have been destroyed in Afghanistan, and the latest development seems certain to provoke more concern.
The United Nations Educational, Scientific and Cultural Organisation, Unesco, has appealed to the Taleban to preserve works of art, and a team of western diplomats is currently in the capital, Kabul, calling for Afghanistan's rich heritage to be preserved.
False gods
In an interview with the BBC's Pashto Service, a Taleban spokesman, Mullah Abdul Hai Motmain, said the statues were being worshipped.
He said it had been the policy of prophets and Islamic holy men from time immemorial to destroy all false gods.
Statues are scattered all over Afghanistan, and include a number of Hindu shrines in Bakhtiar province.
But the most prominent figures are the ancient Buddhas of Bamiyan, where most of the population is still Buddhist.
There has recently been fierce fighting around the town, which has several times changed hands.
Taleban enemies
Mullah Motmain said the people worshipping the statues were enemies of the Taleban. He refused to accept that Islam called for respect for other faiths.
Islam, he said, had defeated and cancelled out all other religions.
With their ultra-conservative Islamic ideology, the Taleban believe depiction of any human figure is blasphemous.
Some also think, mistakenly, that Buddhists worship the Buddha and that the statues are therefore idols.
Until now, the Taleban rulers had said the statues could be preserved, as long as they were not the objects of worship.
Two weeks ago, the movement denied reports circulating in Kabul that more than a dozen non-Islamic artefacts in the National Museum, including a priceless figure of the Buddha, had been destroyed.