The two-week drills - called Balikatan, or "shoulder-to-shoulder" - bring together 6,000 U.S. and 2,000 Filipino troops at a time when Philippine forces are battling militants from the Abu Sayyaf and its allies from the Indonesia-based Jemaah Islamiyah terror network.

About 30 protesters from the left-wing coalition Bayan burned a U.S. flag and chanted "U.S. troops out now!" outside the gate of the military headquarters in Manila, where U.S. Ambassador Kristie Kenney, Philippine Foreign Secretary Alberto Romulo and top military officials led the opening ceremony.

Rallies also were held in at least four southern cities to demand U.S. troops leave because of alleged involvement in combat operations - prohibited by Philippine law - and human rights abuses, activists said.

In Cagayan de Oro, police estimated the crowd at 1,000, including priests and nuns who joined lawmakers and Muslim activists.

In the southern Philippines, where Muslim rebels have waged a decades-long separatist insurgency, U.S. troops will conduct medical missions and repair schools, officials said.

The areas include Jolo island, an Abu Sayyaf stronghold, and central Mindanao, a base of the Moro Islamic Liberation Front, the country's biggest separatist group, now holding peace talks with the government.

Tensions flared recently on Jolo after villagers accused the military of killing seven civilians and an off-duty soldier during operations to hunt down suspected terrorists.

Rawina Wahid, whose husband was killed in the raid early this month, said she was tied up and put on a naval boat with several U.S. Soldiers on board.

President Gloria Macapagal Arroyo has ordered an investigation into the deaths. Last week, U.S. Embassy spokeswoman Rebecca Thompson denied American Soldiers took part in any combat operations.

Military chief Gen. Hermogenes Esperon said the emphasis of the exercises, which have been held since 1981, has shifted to humanitarian assistance, part of efforts to win over local Muslim populations.

America's soft counterterrorism approach here has won praise in contrast to mounting criticism of U.S.-led incursions in Iraq and Afghanistan.

A manhunt continues on Jolo for Abu Sayyaf commanders and two top Indonesian militants wanted for alleged involvement in the 2002 nightclub bombings that killed 202 people on Indonesia's Bali island.

The Abu Sayyaf, blacklisted by Washington as a terrorist organization, has been blamed for deadly bomb attacks, beheadings and high-profile kidnappings, including of Americans.

Use your GI Bill before time runs out!

Sound Off...What do you think? Join the discussion.

Copyright 2008 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

More Military Headlines

• Artilleryman Reenlists for T-Shirt
• No Joke: Bill Murray Leaps 13,000 Feet
• National Guard Prepares for Storm
• Video-games Can Be Tough for Parents
• Movie Review: The Rocker