NEW DELHI, JUNE 1 -- India said today it will send a convoy of relief supplies to northern Sri Lanka, where the government is battling to wipe out strongholds of Tamil rebels.

The Indian government, which has been pressured by its own Tamil citizens to intervene in the week-long Sri Lankan offensive, will send 20 boats carrying food and medical supplies to Sri Lanka's Jaffna peninsula, a Foreign Ministry spokesman said. The convoy will be unarmed and under the supervision of the Indian Red Cross, he said.

{Sri Lankan officials said they considered the Indian decision a violation of Sri Lanka's sovereignty, news agencies reported from Colombo. The Foreign Ministry said the government would consider accepting the shipment, but only after organizing with India the methods for distributing the supplies.

{A Sri Lankan official quoted by Reuter said his government would seek a parliamentary resolution condemning the Indian move as "an infringement of our sovereignty," but said Sri Lanka's tiny force of naval patrol boats would not try to stop the convoy by force.}

The Indian spokesman here denied that New Delhi's move represented interference in Sri Lankan affairs, saying it was "motivated by humanitarian considerations."

Since 1983, the Sri Lankan government, dominated by the country's ethnic Sinhalese majority, has been fighting guerrillas of the Tamil minority who demand cultural and political autonomy. The Tamil rebels have maintained bases in southern India, where they receive strong support from the 50 million Tamils living there.

Last week, the Sri Lankan government launched an offensive, using about 3,000 troops and reported air and artillery bombardments, to try to break the rebels' control over Jaffna. Tamils in India have been outraged by the assault and politicians within Prime Minister Rajiv Gandhi's ruling Congress (I) Party and in the opposition have called for Indian intervention to stop the offensive. The Foreign Ministry spokesman said today that New Delhi would not send arms to the Tamil rebels.

The Sri Lankan government issued a communique saying its forces had completed the first phase of the offensive, taking the rebels' last stronghold on the approaches to the city of Jaffna.

India last week accused Sri Lanka of "carpet bombing" and killing hundreds of Tamil civilians, and Gandhi demanded that Sri Lanka end its drive. The Sri Lankan government says that about 200 have died in the fighting, 37 of them civilians. Over the weekend, Sri Lankan officials denied the bombing allegations and journalists flown over Jaffna reported no evidence of heavy bombing.

India has echoed claims of the Tamil rebels that civilians in the Jaffna area are short of food and other essentials. Official Sri Lankan reports have said its own forces were distributing food in the area and that there was no need for outside supplies. No journalists or other observers have been permitted on the ground in the battle zone, making it difficult to judge the conflicting claims by the government and rebels.