A trio of bombs jolted the jittery Philippines on Monday, killing at least nine people and wounding more than 100 others, police said.
The Muslim extremist group Abu Sayyaf, which is on Washington's list of terror groups, claimed responsibility, calling it retribution for a major, ongoing military offensive against Islamic gunmen in the restive south.
National police head Gen. Edgar Aglipay ordered the 114,000-strong police force to tighten security in vital installations and public places nationwide.
"These are despicable acts of terror, and we ask the people to brace themselves against these attacks on our freedom and security," presidential spokesman Ignacio Bunye said.
"We're not going to sleep tonight," added National Security Adviser Norberto Gonzales.
One bomb exploded on a bus along a busy Manila highway just below a station for an elevated train and near the Intercontinental Hotel. Police said three people were killed and at least 60 others injured as the bus burst in flames. Debris hit two other buses.
The back of the bombed bus was destroyed in the 7:30 p.m. blast and all of the windows were blown out. The charred body of one passenger was still seated with a hand holding the seat railing.
President Gloria Macapagal Arroyo visited the site.
A blast outside the Gaisano Mall in southern General Santos city about an hour earlier could be heard a mile away. Police said at least five people were killed and at least 36 others injured.
Aglipay said the bomb was believed to have been stashed in a bag at a stand for three-wheel taxis about 30 yards from the mall entrance.
Another bomb, believed to have been made from a mortar shell, killed a 12-year-old boy and injured at least eight people when it went off almost simultaneously at a bus terminal in Davao, also in the southern Philippines, home to a restive Muslim minority, terror groups and criminal gangs. Mayor Rodrigo Duterte called it "the handiwork of terrorists."
Abu Sayyaf leader talks to radio
"You can attribute this to us," an Abu Sayyaf leader, Abu Solaiman, told DZBB radio 20 minutes after the first two blasts.
"There is one more to come," he said before the Manila bombing.
In a second call, Solaiman said the bombings were a Valentine's Day "gift" to President Gloria Macapagal Arroyo.
"Our latest operations -- planned and executed with precision by the gallant warriors of Islam -- is our continuing response to the Philippine government's atrocities committed against Muslims everywhere," Solaiman said. "We will find more ways and means to inflict more harm to your people's lives and properties."
Officials had worried about possible terrorist attacks as the military carries out an all-out assault on Jolo island against a group of gunmen who recently attacked troops, sparking clashes that have killed at least 60.
The gunmen are believed to include followers of jailed Muslim leader Nur Misuari, backed by Abu Sayyaf members.
"We warned our units about these threats as early as last week," Aglipay said.
Earlier bombings, arrests
A bombing killed at least 14 people and wounded 70 others Dec. 12 in General Santos, a bustling, predominantly Christian city of 500,000 people about 620 miles south of Manila.
Five people, all reportedly with links to the Abu Sayyaf, were arrested in connection with the attack.
The Abu Sayyaf also claimed responsibility for a bomb that exploded on a ferry in Manila Bay last year and killed more than 100 people.
Near-simultaneous bombings, also blamed on Muslim extremists and the regional terror group Jemaah Islamiyah, killed 22 people in Manila on Dec. 30, 2000.