Five people have been killed and more than 50 wounded in two explosions in the southern Philippines. The attacks occurred as the main contingent of U.S. troops began arriving for controversial joint counter-terrorism exercises.
The first attack occurred at dawn Saturday at a public market in Jolo City, one thousand kilometers south of Manila.
Hours later a grenade exploded in a movie theater at a popular mall in downtown Zamboanga. The mall is across the street from the site of a similar attack last October that killed six people and wounded 56 others.
A military commander blamed the bombing in Jolo, in Sulu province, on the Abu Sayyaf, saying the group sent letters to schools a few days earlier threatening attacks if a recent military offensive continued.
The Philippine military two weeks ago launched a major offensive against the Abu Sayyaf in Sulu after a series of ambushes in which nearly a dozen soldiers were killed.
The United States has linked the Abu Sayyaf to the al-Qaida terrorist network.
In response to the threat, Washington is sending more than 600 troops to the Zamboanga area to help train the Philippine military. This is the most significant expansion of the American-led war on terrorism outside of Afghanistan.
Saturday's bombings occurred as U.S. troops arrived to launch joint exercises against the Abu Sayyaf on Basilan Island.
Several large U.S. transport planes Saturday delivered American troops and equipment to Zamboanga. And U.S. advance troops arrived on Basilan to prepare for the deployment next week of the main U.S. contingent.
Public opinion polls say the joint exercise is supported by a majority of the Philippine population.
But a number of groups oppose the return of U.S. troops to the archipelago after a 10-year absence and have staged almost daily demonstrations since the announcement.