Kabithigollewa, Sri Lanka ? Suspected Tamil separatists attacked a crowded bus Thursday, triggering a pair of hidden bombs that killed at least 64 people – the worst violence since a 2002 cease-fire began unraveling in recent months.

With peace talks largely abandoned, the attack edged this tropical island nation off India’s southern tip further toward all-out war in a conflict that killed 65,000 people before the truce. The government quickly launched retaliatory airstrikes on rebel areas.

The dead included at least 15 children, their blue school uniforms coated with blood and gore as authorities laid out corpses at a hospital in the island’s north so relatives could identify them. At least 78 people were wounded in the attack.

The rebels, a well-armed movement that began fighting in 1983 to create an independent homeland for the ethnic Tamil minority, denied responsibility for the attack. They suggested it was done by shadowy forces they accused of trying to create unrest.

But Sri Lanka’s government, which is dominated by the majority Sinhalese, insisted rebels of the Liberation Tigers of Tamil Eelam movement were responsible.

Soldiers patrol near a bus overturned by a landmine blast Thursday in Kabithigollewa, Sri Lanka. Sri Lanka's air force bombed Tamil rebel-held areas in the northeast on Thursday, after a powerful mine blast ripped through a bus, killing at least 64 people, the army said.

“This is a barbaric act of the LTTE,” said government spokesman Keheliya Rambukwella. “Their aim is to provoke a backlash.”

The bus was blown up with a pair of land mines hung from a tree and detonated by remote control, said a military spokesman, Brig. Prasad Samarasinghe. Rigging bombs to trees or bicycles is a common rebel tactic, so the ground does not absorb much of the blast, officials say.

Police said most of the victims were Sinhalese, the group the rebels accuse of discriminating against Tamils.

Officials said many passengers were headed to the funeral of a policeman killed Monday in another attack blamed on rebels.