MANILA - The death toll from an attack on a group of journalists and politicians in the lawless southern Philippines is set to climb above 22 with the discovery of shallow graves, officials said Tuesday.

The victims were among a group of more than 40 people abducted by gunmen linked to a powerful politician on the southern island of Mindanao on Monday.

Military spokesman Lieutenant-Colonel Romeo Brawner told AFP that 22 bodies had been recovered as of Tuesday morning.

"Most of the bodies bore gunshot wounds," he said.

Interior Secretary Ronaldo Puno confirmed the official death toll as 22, but said more bodies had since been recovered from shallow graves and even more were expected to be found.

"They are still looking for some missing persons. A number of other bodies were found. I can't really reveal the details now. It's a large number," Puno told the ABS-CBN television network.

"It's a big area where these bodies were found. They are finding a couple of bodies every couple of hours or so. We are not closing the count on this until we search the whole area."

He said the killings occurred on a remote farming area near the town of Ampatuan on Mindanao island. One of the investigators on the scene, Chief Superintendent Felicisimo Khu, said police had established two main areas where bodies were suspected to have been buried.

Of the 22 bodies recovered, Khu said 14 were women and eight were men. "All were shot at close range," he said, adding 15 of them were believed to have still been inside their vehicles when killed.

Asked about the allegations by some of the victims' relatives that the murdered women were also raped, Khu said: "We cannot confirm that although all the women had their pants unzipped."

Brawner said the group had been abducted by gunmen linked to Andal Ampatuan, leader of a powerful political clan in the area, and that the victims included the wife of his rival, Esmael Mangudadatu.

He said the military was searching for the other people still missing, as well as hunt down the gunmen.