A number of bomb attacks in the Philippines have left at least 11 people dead and nearly 130 wounded.
The explosions, which took place in the business district of the Philippine capital and in two southern cities, have been blamed on Muslim rebels.
"The ground was shaking," said a man in the southern city of General Santos after four people were killed at a shopping mall.
"The people were screaming and running in all directions."
Security forces quickly blamed Abu Sayyaf, a small Muslim rebel group associated with al Qaeda, for the improvised bomb in General Santos and a grenade attack at a bus terminal in Davao that killed a young boy.
In Manila, six people were killed in an explosion on a bus at a commuter terminal near the crowded Glorietta mall, major hotels and the nation's financial and diplomatic core.
"There's a strong possibility the attacks could all be linked," said Norberto Gonzales, the national security adviser.
"They have admitted two. We will know more later."
A police intelligence official told Reuters investigators had not ruled out a role by Jemaah Islamiah, a regional network of militants linked to al Qaeda and the suspected fund-raiser for previous attacks by Abu Sayyaf and other Philippine groups.
Abu Solaiman, a senior Abu Sayyaf leader, said on radio his group carried out the attacks in General Santos and Davao to punish President Gloria Macapagal Arroyo for a heavy military offensive on the southwestern island of Jolo, its stronghold.
"This is our Valentine's gift for her," Solaiman said.
In February 2004, more than 100 people died when a bomb planted by Abu Sayyaf sank a ferry at the mouth of Manila Bay.