Philippine military officials say they have uncovered a plot by Islamic militants linked to al-Qaida to assassinate President Gloria Arroyo.

The officials say the plot was hatched by members of the Philippine-based Abu Sayyaf group and the Indonesian-based Jemaah Islamiyah.

Brigadier General Romeo Prestoza, the chief of Mrs. Arroyo's security detail, told reporters Thursday that other high-profile targets were included in the plot on the president's life. He says the discovery of the plot forced Mrs. Arroyo to cancel an upcoming trip to the northern resort city of Baguio.

The Philippine military has been put on full alert after officials revealed that a protest rally calling for the president's resignation may be infiltrated by rebels.

Mrs. Arroyo's critics plan to stage a demonstration Friday in Manila's business district, Makati, over allegations that her husband accepted bribes and kickbacks in relation to a $330 million telecommunications deal with a Chinese firm.

Mrs. Arroyo has since canceled the contract.

Some information for this report was provided by AFP and AP.