COLOMBO, Sri Lanka - Suspected Tamil Tiger rebels blew up two passenger buses in Sri Lanka on Friday, killing 23 people and raising the specter of an escalating cycle of attacks on civilian targets.
An additional 67 people were wounded in the attacks, which came two days after a bombing that targeted civilians in Colombo, the capital. The government also blamed that blast on Tamil Tiger rebels, who have made such attacks a hallmark of their 25-year fight against Sri Lanka's government.
"This could be the start of a worsening cycle of targeting civilians," said Jehan Perera of National Peace Council, an independent activist group.
He said the attacks were likely "tit-for-tat kind of retaliation," by the rebels, who accuse the military of killing ethnic minority Tamil civilians with mines and air raids.
"The government must also be careful with its own operations," he said.
The government denies targeting civilians.
Rebels did not comment on the attacks Friday, but if they are responsible it would indicate an ability to strike deep inside government territory despite a maze of security checkpoints around the capital and its suburbs.
The first bomb was detonated along a roadside about 7:35 a.m. in the Colombo suburb of Moratuwa as a passenger bus went by, said military spokesman Brig. Udaya Nanayakkara. It killed 21 people and wounded 47.
A curfew, imposed in the area to allow security forces to search for suspected rebels, was lifted later in the day, he said.
The explosion shattered the vehicle's windows and peppered it with shrapnel. A 45-year-old man who identified himself only as Nalaka said he was thrown from his motorcycle by the explosion.
"When I got up I saw the bus and quickly got into it. Some people lay dead. Some others were bleeding," he told AP Television News.
Hours later, a bomb tore through a bus in the hills of central Sri Lanka, east of the capital, killing two passengers and wounding 20 other people, said police spokesman Ranjith Gunasekara.
President Mahinda Rajapaksa called on Sri Lankans to "remain vigilant against the forces of terror," after Friday's first attack.
With much of the fighting taking place hundreds of miles to the north, the recent attacks have shaken the south, home to Sri Lanka's Sinhalese majority, and left residents fearful.
"I don't know how this war is being fought in the north. I see that only on the television. But, it now seems the war has come to the capital," said Roshan Dhammika, a 30-year-old who drives a motorized rickshaw.
The recent attacks seemed to boost already strong support for the war among people in Colombo.
"What else can you do against a ruthless terrorist group. The LTTE now wants to stop operations in the north as they are suffering defeats. That's why they target civilians," said Ganesh Wijenayake, a 45-year-old businessman in Colombo, using a common acronym for the insurgents.
Blamed for scores of suicide bombings and other attacks on civilians, the Tamil Tigers are listed as a terrorist group by the U.S., the European Union and India. They are believed to have been behind a blast Wednesday that targeted a passenger train in Colombo wounding 19 people.
Formally known as the Liberation Tigers of Tamil Eelam, the rebels have fought since 1983 to create an independent homeland for Sri Lanka's Tamil minority. More than 70,000 people have been killed.
Since a peace process broke down nearly two years ago, fighting between the Tigers and government forces has steadily escalated.
But the rebels still run a de facto state in much of northern Sri Lanka, and the government says it plans to crush the insurgents by year's end.
More than 200 civilians have been killed by bombings in rebel and government territory this year, according to the U.N. Office for the Coordination of Humanitarian Affairs.
