COTABATO, Philippines - Philippine authorities will resume the search Wednesday for more victims of a massacre that left at least 46 people dead, amid fears the death toll could top 50, the military said.

The mass killings of aides and relatives of a local politician in the southern Philippines, as well as journalists accompanying them, occurred on Monday in remote farming area on the volatile southern island of Mindanao.

"The search will continue in the general area today," the local military spokesman, Lieutenant-Colonel Jonathan Ponce, told AFP.

"They say there could be more than 50 victims, but only 46 bodies have been recovered so we would be looking for more."

The bodies of at least 13 journalists and relatives of the local politician, Esmael Mangudadatu, were found buried in hastily dug mass graves or dumped on the side of the road in Maguindanao province.

The military said the main suspects in the abductions and murders were gunmen hired by the Maguindanao governor, Andal Ampatuan, and his son who has the same name.

Relatives of the victims and witnesses have said the powerful political clan wanted to stop Mangudadatu from challenging Ampatuan junior for the post of governor in next year's national elections.

The victims were seized as they were travelling in a convoy with Mangudadatu's wife as she went to an electoral office to register her husband to run for governor.

Three policemen believed loyal to the Ampatuans have been detained for their alleged involvement in the murders.

Following the masscare, President Gloria Arroyo imposed emergency rule on Maguindanao, neighbouring Cotabato city and nearby Sultan Kudarat province. Ponce said soldiers in the troubled region, known for its political warlords as well as a long-running Muslim separatist insurgency, were manning checkpoints on key highways to prevent the movement of weapons.