ICA, Peru--The leaders of Peru, Colombia and Bolivia conferred in this desert city yesterday, guarded by thousands of police and soldiers, on a common strategy against the multibillion-dollar cocaine trade in their Andean nations.

President Alan Garcia of Peru met Presidents Virgilio Barco of Colombia and Jaime Paz Zamora of Bolivia at an air force base near Pisco, 45 miles northwest of Ica. They flew by helicopter to the Las Dunas hotel outside this city of 350,000 in the coastal desert 185 miles southeast of Lima.

An army battalion of 300 guarded the hotel, which is surrounded by extensive gardens. Three thousand plainclothes policemen circulated in the city.

Heavy security was ordered in case of attacks by the Shining Path, a Maoist guerrilla group that has fought Peruvian governments since 1980.

A bomb exploded before dawn Tuesday in Trujillo, a northern city where five Latin American foreign ministers were meeting to prepare the agenda for a summit of the Group of Eight countries that begins today.

It went off at the offices of a public housing agency, damaging the building but causing no injuries. Police said no group claimed responsibility.

Ica suffered two brief blackouts yesterday morning, but officials said technical problems caused them, not sabotage.

Garcia, the Peruvian president, said the drug summit "will represent our point of view on how to confront the escalation of violence that drug traffickers have unleashed in our countries, and also our perspective on the United States president's proposals."

The three countries have criticized President Bush's emphasis on military-style repression of the drug trade. They say it should be accompanied by more economic aid to provide alternative crops or sources of income for the hundreds of thousands of peasants who grow coca.

Barco began a crackdown on Colombian cocaine barons Aug. 19 and has received $65 million worth of U.S. military aid to help in the effort.

Garcia has been especially vocal on what he considers the limitations of the Bush plan, which includes $261 million for the three countries, mainly in the form of weapons.

Peru and Bolivia produce more than 90 percent of the world's coca. Colombian drug cartels turn semi-refined coca paste from the two countries into pure cocaine and smuggle it to the United States and Europe.

Hundreds of thousands of peasants in Peru and Bolivia live by growing coca. Officials of both countries say there is little hope of eradicating the crop unless the growers have another way of making a living.

Colombia says it needs stable world prices for coffee, its main legal export. Otherwise, the Colombians say, the cocaine-dependent economy could collapse if the war against drug trafficking was successful.

"It's not a problem of donating some helicopters, sometimes very old helicopters, or donating rifles or bullets," Garcia said. "It would be enough to offer a good price and a guaranteed market for the products that could substitute for coca."

Peru has an added worry because of support the Shining Path has among the peasants who grow coca. The rebels protect the peasants against a U.S.-financed coca eradication program, in return collecting a "tax" of 10 to 15 percent of their earnings.

Peruvian officials fear Shining Path ranks will expand swiftly if the government succeeds in reducing the cocaine trade without providing alternate sources of income to peasants.

"We have a double problem in the Huallaga Valley--coca cultivation and subversion," Garcia said. "Unless coca substitution is gradual, all we will acheive is to make poor peasants even poorer and push them into the arms of the subversive movement."