General Nhek Bunchhay, deputy army chief of staff, said the guerrillas planned to let Pol Pot be judged by an international tribunal for his role in the genocidal regime he led between 1975 and 1979, which caused the deaths of 2 million Cambodians.
Gen Bunchhay had flown to the rebel stronghold of Anlong Veng, in northern Cambodia, to cement the defection of about 1,000 guerrillas from the Khmer Rouge.
The report on Khmer Rouge clandestine radio claimed that Pol Pot had "confessed", although it was not immediately clear to what.
Amid intense speculation over his whereabouts, the radio said Pol Pot's surrender was "the beginning of a new era in Cambodian history", and that a "dark cloud had now disappeared from above the country".
Government forces have pledged to stand Pol Pot, 69, before an international war crimes tribunal for crimes against humanity. But there has been no independent confirmation of his surrender and officials in the Cambodian capital, Phnom Penh, greeted the report with scepticism. "We must be careful about this," said Hun Sen, one of the country's two vying prime ministers. "Everything is still a mystery. It is dangerous." If the report were true, he said, Pol Pot should be handed over for trial.
The reported surrender is the latest in a series of unconfirmed events that have generated excitement about the possibility of seeing one of the 20th century's most hated despots brought to justice.
"If this is true, then it is the very best thing that has happened for Cambodia, and good for the rest of the world also," said Serai Kosal, chief security adviser to Prince Norodom Ranariddh, the country's other prime minister.
Last week Prince Ranariddh said Pol Pot and a small group of loyalists had fled his remote Anlong Veng jungle stronghold after an unpopular internal purge had turned his supporters against him.
Since the horrors of his brutal regime between 1975 and 1979, in which millions of Cambodians were executed, died of starvation or mistreatment, Pol Pot's name has become synonymous with evil. He has been described as "Asia's Hitler".
But as the curtain finally descends on Pol Pot and the Khmer Rouge he has led for a quarter of a century, the real state of "Brother Number One" remains shrouded in uncertainty and rumour.
Secretive to the point of obsession, Pol Pot, a former teacher whose real name is believed to be Saloth Sar, has hidden himself from the outside world. A single photograph of him exists from the Eighties and his whereabouts and health have been the subject of widespread speculation over the years. A year ago, he was rumoured to be dead.
Last week, he was reported to be alive and well, but battling against breakaway Khmer Rouge dissidents.
They were reported to be embittered against Pol Pot for ordering the execution of Son Sen, his aged defence chief, and the arrest of other top Khmer Rouge figures.