COLOMBO, SRI LANKA, JUNE 2 -- The government accused Tamil separatist guerrillas of murdering 33 people, including 29 Buddhist monks, aboard a bus today in the latest massacre of Sri Lanka's ethnic conflict.

A government spokesman said guerrillas believed to belong to the Liberation Tigers of Tamil Eelam stopped a bus on a remote country road in the eastern district of Amparai, about 125 miles from Colombo, and killed the passengers.

Eleven other monks were wounded but survived.

{In Madras, India, where several Tamil rebel organizations are based, the Liberation Tigers denied involvement in the massacre, calling the government allegation "unfounded and malicious," United Press International reported.}

It was the biggest massacre of Buddhist monks from Sri Lanka's majority Sinhalese community in the island's four-year-old ethnic conflict, which has claimed more than 4,500 lives.

The government, meanwhile, headed for confrontation with India over New Delhi's decision to send relief supplies to the 800,000 people of the northern Jaffna Peninsula. Tamil rebels have said Jaffna's inhabitants were starving because of a government blockade and antiguerrilla offensive.

A Foreign Ministry statement said Jaffna did not need emergency supplies and Sri Lanka strongly objected to any unilateral action by India.

"Any such action will be considered a violation of the independence, sovereignty and territorial integrity of Sri Lanka," the ministry said.

It said India had misinterpreted a government statement last night as Colombo's agreement to accept the 20-boat flotilla loaded with wheat, rice, sugar, kerosene and medical supplies. In Rameshwaram, India, across the Palk Strait from Jaffna, the director of the convoy said it had been delayed following the Sri Lankan objection.

Sri Lanka's Tamil minority receives strong support from the 50 million Tamils in southern India.

The alleged massacre of the Buddhist monks was expected to cause an uproar among Sinhalese, most of whom are Buddhist and who comprise about 70 percent of the 16 million population.

The nation's 30,000 monks are held in high esteem and wield considerable influence. They consider themselves the guardians of their community.

Militant monks have long pressed President Junius Jayewardene to take a tough stand against the Tamil separatists, who are fighting to set up a homeland in the north and east of the island.

Today's massacre, if the government account is accurate, was the second against Sinhalese civilians since the Army launched its controversial "Operation Liberation" to wrest parts of the northern Jaffna peninsula from the Tigers on May 26.

On May 29, the government has said, Tamil rebels hacked to death eight villagers in the eastern Batticaloa region in apparent reprisal for the offensive.

The reported killings today followed charges by Tamil rebels and the Indian government that Sri Lankan troops in the Jaffna Peninsula had killed hundreds of Tamil civilians in the eight-day offensive against the Tigers. The government has denied those charges.