U.S. military cargo planes brought more troops and equipment to the southern Philippines on Sunday amid growing protests against American involvement in the government's efforts to quash Muslim guerrillas.

Three U.S. Air Force C-130s arrived at an air base in the southern port city of Zamboanga carrying several soldiers, a forklift, a power generator, engineering equipment and a truck and trailer loaded with communications gear.

Capt. Noel Detoyato, spokesman for the Philippine military's Southern Command, said the Americans were part of a contingent that would train Filipino special forces battling Abu Sayyaf guerrillas in the jungles of nearby Basilan island, 540 miles south of Manila.

U.S. and Philippine officials say the Abu Sayyaf have been linked with Usama bin Laden and his Al Qaeda terror network.

Journalists were barred from interviewing the Americans, who were dressed in camouflage and carried no visible firearms.

The gradual U.S. military buildup in Zamboanga and Basilan is part of preparations for a six-month training exercise in which small teams of armed U.S. Army Special Forces are expected to enter combat zones to assess their Filipino counterparts and their needs.

Some 660 U.S. soldiers, including 160 Special Forces, are to take part in the training exercise. The U.S. troops cannot engage guerrillas but can defend themselves.

Welcomed by the ill-equipped Philippine military, the U.S. involvement has raised concerns over legal restrictions on foreign troops and rekindled anti-American sentiment in the former U.S. colony.

Hundreds of leftist activists used protests on the first anniversary Sunday of Arroyo's rise to power to demand American troops leave the country.

Outside the presidential palace in Manila, protesters hurled tomatoes at a giant effigy of Arroyo on a mock throne adorned with American flags and a sign that read "Traitor." Another placard read "U.S. terrorist troops, go home!"

Arroyo has come under fire from leftist groups for allowing the U.S. military to get involved in operations against the Abu Sayyaf, who have been holding an American couple since May and killed another American hostage last year.

While street protests against the planned U.S. presence have failed to draw mass crowds in the Philippines in recent weeks, organizers predict participation will grow in coming days.

The opposition to the U.S. military presence prompted President Gloria Macapagal Arroyo to call for a meeting this week of the National Security Council, an advisory group that includes opposition politicians and former presidents.

"It's a slap on our sovereignty," protest leader Teodoro Casino said.

In the predominantly Muslim city of Marawi in the south, about 500 students yelled "Allahu Akbar!" — God is great — while burning a U.S. flag.

"If Americans would end up as casualties, they would retaliate," said Mahoud Gaima, a leader of a Muslim group called the Bangsa Moro Youth Assembly. "Many of us could end up as innocent victims."