The commandos had entered the far-flung village of Tukanalipao at dawn looking for a top terror suspect, but had a "misencounter" with members of the Moro Islamic Liberation Front and other insurgents, Mayor Tahirudin Benzar Ampatuan of Mamasapano town told The Associated Press by telephone.
Other insurgents in the area later joined in fighting the outnumbered police forces, the mayor said. The Moro group signed a peace deal with the government last year.
The fighting in the marshy village of corn and coconut plantations subsided after several hours when members of a cease-fire committee and foreign truce monitors intervened, Ampatuan said, adding he deployed a team of village leaders and guards, who saw more than 30 of the slain commandos scattered in the battle scene.
"What they described to me was gruesome," Ampatuan said. At least two Philippine security officials told The AP that the target of the police commandos was Zulkifli bin Hir, a Malaysian terror suspect known also as Marwan, who has been blamed by U.S. And Philippine authorities for several deadly bombings. Marwan is believed to have been hiding in the country's south since 2003.
The villagers managed to extricate only five of policemen's bodies by nightfall because they were afraid of their safety amid sporadic gunfire and the darkness in the village, which was 2 to 3 kilometers (1.2 to 1.9 miles) from the nearest main road, Ampatuan said.
It remains unclear how many police commandos entered the village, he said, adding the death toll may increase.