The Philippine army has launched an offensive against Muslim separatist bases in the southern Philippines, and says at least 50 guerrillas have been killed.
Philippine military officials say they have launched rockets, bombs and artillery at jungle strongholds held by the separatist Moro Islamic Liberation Front.
The regional military chief, Major General Roy Kyamco, says the army fired more than 135 artillery rounds on the Moro Islamic Liberation Front positions in central Mindinao, killing dozens of rebels.
But a rebel spokesman denied the military reports.
The military operation follows Philippine President Gloria Arroyo's authorization of aerial and artillery attacks on what she called "embedded terrorist cells" in the south of the country.
She did not name specific targets. The Moro Islamic Liberation Front has been blamed for bombings and attacks in recent months that have killed more than 200 people.
The government in Manila has suspended peace talks with the rebels, and threatened to declare the Moro Islamic Liberation Front a terrorist group, unless it renounces violence, and hands over those responsible for the attacks.
The rebels, which number more than 12,000, have been fighting a 25-year guerilla campaign for an Islamic state in the southern third of the largely Roman Catholic Philippines.
President Arroyo has been a staunch supporter of the U.S.-led war on terrorism, following the September 11, 2001, attacks on the United States. The Philippines became the second country, after Afghanistan, where U.S. troops were deployed to help wipe out terrorism.
Joint training exercises in the southern Philippines have centered on the Muslim rebel group, Abu Sayyaf, known for violent kidnappings for ransom.
Mrs. Arroyo will be in Washington this week to discuss new bilateral counter-terrorism measures.