The latest to receive the threats was Mayor Romeo Araña of Midsayap, a booming town of mixed Muslim and Christian settlers in North Cotabato.
The police command here deployed dozens of policemen around Catholic churches here last Sunday after the threatening text messages circulated.
Cotabato City Vice Mayor Guiapal Guiani Jr. said in a radio interview that the threats, though seemingly coming from pranksters, should not be ignored.
Policemen and soldiers in Midsayap and surrounding towns have been visible along thoroughfares and around worship sites to thwart bomb attacks.
Col. Franklin del Prado, spokesman of the Armys 6th Infantry Division, said they are not taking any chances.
"In Central Mindanao, there has no precedent of any Islamic or Christian worship site being attacked by terrorists. This is because Muslim and Christian religious leaders have been helping one another secure their worship sites and promote religious solidarity in this part of the country," he said.
Even so, Del Prado said they have put tight security measures in place to prevent "third parties" from ruining the solidarity of the Muslims and Christians in the region.
There have been persistent reports that Jemaah Islamiyah operatives, among them Dulmatin and Umar Patek, were being coddled by rogue secessionist guerrillas in many parts of Central Mindanao, particularly in the Liguasan Marsh, a 220,000-hectare delta at the boundary of North Cotabato, Sultan Kudarat and Maguindanao.