MANILA - A senior policeman in the southern Philippines has been sacked and detained after witnesses said he was present at the massacre of a group of politicians and journalists, police said Tuesday.

"Chief Inspector (Zukarno) Dicay, the assistant provincial director, has been relieved," national police spokesman Chief Superintendent Leonardo Espina said on television network ABS-CBN.

"He is under investigation and is under restriction."

Dicay was the second highest-ranking police official in Maguindanao province, where at least 22 people were killed on Monday in a kidnapping that authorities says is linked to a power struggle between rival clans.

Gunmen abducted the victims as they were travelling on a highway, took them to an isolated area and murdered them, police and the military said.

"He (Dicay) was seen at the scene of the crime together with some CAFGUs," Espina said, referring to a members of the Citizen Armed Forces Geographical Unit militia who are trained by the government to fight local insurgencies.

The military said the Ampatuan clan, which has a political lock on the areas of Maguindanao where the murders took place, were the prime suspects.

"The suspects are bodyguards of Ampatuan, local police aides and certain lawless elements," military spokesman Lieutenant-Colonel Romeo Brawner said.

Among those killed were relatives of Esmael Mangudadatu, who was planning to run for governor in next year's national elections against a member of the rival Ampatuan clan.

Journalists accompanying the Mangudadatus to an electoral office were in also murdered.