Philippine officials say suspected Islamic militants have thrown a grenade into a concert venue in the southern Philippines, wounding 16 people.
The grenade exploded Tuesday as a concert was taking place in the city of Isabela on Basilan island.
Philippine officials say they suspect Abu Sayyaf militants carried out the attack in retaliation for a military offensive against the al-Qaida-linked group in Basilan.
In other violence, gunmen opened fire on a United Nations aid truck on the southern Philippine island of Mindanao late Sunday, killing a Philippine aid worker.
The truck had been distributing rice from the U.N. World Food Program to Philippine refugees displaced by fighting between government troops and Muslim rebels. Two other men in the vehicle were not hurt in the attack.
Philippine military official Colonel Rey Ardo says the gunmen likely were highway bandits seeking to rob the truck.
Violence has escalated in the southern Philippines since August, when the country's Supreme Court struck down a government-rebel peace deal.
Rebels from the Moro Islamic Liberation Front are fighting for a Muslim homeland in the southern Philippines, a Muslim-dominated region in a predominantly Christian country.
Philippine journalist Al Jacinto says the violence has dampened the holiday spirit in the region ahead of Christmas on Thursday because many Christian residents are too afraid to shop.
President Gloria Arroyo has authorized a peace panel to revive talks with the Muslim rebels to try to end the decades-old conflict.
Some information for this report was provided by AFP, AP and Reuters.