The $1.3 billion U.S. aid package for Colombia includes the largest build-up in military assistance to any Latin American country since the civil war in El Salvador in the 1980s. 

The package is a tangible sign of U.S. endorsement of the Colombian military offensive against the narcotics trade protected by guerrillas, the focus of President Bill Clinton's one-day trip to Colombia on Wednesday. 

Colombia, the world's top producer of cocaine and a growing source of heroin, is now the third biggest recipient of U.S. aid after Israel and Egypt. 

The two-year package, adding to $330 million in previously approved U.S. aid, will give Colombia's army and police 60 military helicopters, including 18 modern Blackhawk helicopters at $13 million a piece. 

Other programs are meant to spur economic development, protect human rights and strengthen democratic institutions weakened by decades of armed conflict. 

Details of the package: 

Army: the largest component of the U.S. aid package is $390 million to train and equip two Colombian army battalions for anti-drug actions. Their purpose will be to protect police from Marxist guerrillas when officers destroy coca and opium poppy plantations in southern Colombia. 

The main hardware items are 16 modern UH-60 Blackhawk helicopters (208 million) and 30 of the older UH-1H Huey helicopters (60 million) to deploy the battalions. 

Police: the Colombian National Police will get $115.6 million for two Blackhawk helicopters and 12 UH-1H Hueys, as well as aircraft to spray drug crops. 

Economic Development: the U.S. aid provides $81 million to encourage Colombian peasants to voluntarily destroy their lucrative drug fields and switch to legal crops. 

Drug Interdiction: the package includes $130 million to improve the interception of drug flows. More than half of the funds will actually go to the U.S. Customs Service to upgrade radar systems on four of their P-3 airborne early warning planes that track traffickers crossing the Caribbean to the United States. 

The U.S. package also provides assistance for some of the hundreds of thousands of Colombia's internal refugees who have fled the violence, and funds to help demobilize and rehabilitate child soldiers recruited by the guerrillas. 

The U.S. Congress put a cap of 500 on the number of American military personnel in Colombia, and 300 for American civilian contractors. 

But the legislation allows the president to waive the cap for 90 days in the event that U.S. soldiers are "involved in hostilities." 

The U.S. package is governed by the so-called Leahy Amendment, which monitors U.S. military aid to Colombia to ensure that no assistance goes to units involved in human rights violations or connected with right-wing paramilitary groups held responsible for massacres of peasants. 

Congress stipulated that any helicopter found to be used in aiding paramilitary groups "shall be immediately returned to the United States." 

But in signing the package, Clinton had to waive six of seven conditions Congress set for granting the aid to Colombia, including proof that the Colombian government was vigorously prosecuting paramilitary leaders and military personnel that abetted them.