COLOMBO, Sri Lanka - Sri Lanka celebrated the 60th anniversary of its independence today amid a heavy security clampdown.

No attacks were reported in Colombo, the capital, where the main celebrations took place.

But Tamil rebels are suspected of being behind the bombing a civilian bus in the Welioyo region, 240 kilometres northeast of the capital. Military officials say the bombing killed 12 civilians and wounded 17 others.

Another roadside bombing in the southeastern town of Buttala killed one soldier and injured two others.

The blasts came amid a wave of attacks targeting civilians across Sri Lanka.

On Sunday, a female suicide bomber blew herself up inside Colombo's main railway station, killing 11 people and wounding 92 others. A day earlier, a bomb on a bus killed 18 people, mostly Buddhist pilgrims, in the central town of Dambulla.

In an attempt to block such attacks in the capital, troops sealed off many roads and a major cellphone operator shut off its text messaging service throughout the morning as officials and residents gathered for the national ceremony.

President Mahinda Rajapaksa railed in a televised speech against the Tamil Tiger separatist rebels and said current economic and security difficulties would be over soon.

He reiterated the government's vow to crush the rebels after decades of warfare, despite an escalation of the conflict in recent months.

"Our defence forces have achieved victories that were never before seen,'' he said. "Terrorism is facing a defeat that it has never before faced.''

Top government officials have said they hope to defeat the rebels by the end of the year.

The independence celebration began with a 21-gun salute and a parade by hundreds of army, navy, air force and police officials, along with tanks, artillery guns and multiple rocket launchers.

Twelve naval gunships and fast-attack craft sailed off the coast, while 26 fighter jets and attack helicopters flew overhead.

Thousands of troops, local dancers and religious leaders paraded along Colombo's coastal road in the independence celebration.

The Tamil Tigers have been fighting since 1983 for an independent homeland for ethnic minority Tamils after decades of marginalization by Sinhalese-dominated governments. More than 70,000 people have died.

A 2002 ceasefire ushered in several years of calm and fostered hopes that peace would prevail, but the truce broke down, with renewed fighting over the last two years claiming some 5,000 lives.

The government officially pulled out of the ceasefire last month and forced independent Nordic monitors to leave the country.

The government ousted the guerrillas from their strongholds in the east last year, and daily fighting rages along the front lines in the jungles of the north, where the rebels still control a de facto state.

A string of battles in the north Sunday killed 36 rebels and one soldier, the military said Monday. The rebels were not available for comment, but the two sides routinely give widely differing death tolls.

The government blames the rebels for the recent attacks on civilian targets inside government-held territory, which continue despite a maze of checkpoints throughout the country.