Ending a 20-day holiday truce, Marxist-led Colombian guerrillas launched simultaneous attacks on four southern towns Tuesday, laying waste three police headquarters, part of a mayor's office and a bank, the government reported today.

The attacks--carried out by 300 members of the Revolutionary Armed Forces of Colombia (FARC), Colombia's largest guerrilla group--left three policemen and a civilian dead, officials said. Army troops repelled the guerrillas in a counterattack, killing more than 20 rebel combatants, the military reported.

The renewed rebel attacks coincided with a Clinton administration proposal to provide $1.3 billion in additional aid over two years to help this Andean nation fight the guerrillas--who authorities say earn millions of dollars protecting drug traffickers in the large section of the country under their control.

Colombia has already been allocated almost $300 million in U.S. aid, bringing the two-year total to $1.6 billion in what the administration has said is a firm commitment to help President Andres Pastrana's government combat the flow of Colombian cocaine and heroin to the United States. The new aid money makes the country the third-largest recipient of U.S. military assistance, behind Israel and Egypt.

Further underlining the U.S. commitment, Secretary of State Madeleine K. Albright has scheduled a visit here this weekend to discuss the new aid package.

Pastrana "has a strategy that he believes makes sense for . . . addressing the drug problem," said White House spokesman Joe Lockhart. "We have an interest in helping them do that because of our own national security interests."

The attacks Tuesday occurred in the state of Narino, a mountainous region along the Ecuadorian border known for its vast opium poppy and coca fields, the raw materials for heroin and cocaine.

The rebels had been dormant since Dec. 20, complying with a government request for a Christmas cease-fire. Peace talks are scheduled to resume Thursday.

Both the U.S. and the Colombian governments have said the country's 15,000 FARC guerrillas have financed much of their 35-year-old campaign by taxing drug traffickers, processors and farmers who grow the coca and opium poppies. U.S. officials have said that their main goal is to stanch the flow of drugs but that U.S. assistance can also be used to combat the guerrillas to the extent their activities help the drug trade or hinder attempts to rein it in.

The southern portion of the country is the main target area for these efforts. Most of the U.S. money would go toward training three more army anti-drug battalions and providing Colombia with 30 Black Hawk and 33 UH-1N Huey helicopters, other types of aircraft, radar equipment and intelligence gathering gear. Colombia inaugurated its first U.S.-funded 1,000-member rapid deployment force last year.

The aid would form part of Pastrana's $7.5 billion "Plan Colombia"--$3.5 million of it in foreign aid--which is designed to suppress drug trafficking as well as shore up the country's ailing economy. "I want to emphasize the fact that the U.S. government has embraced our integrated strategy to create employment, peace and institution-building," a delighted Pastrana told Colombian reporters.

The U.S. package calls for $145 million in alternative economic development, including crop substitution programs for farmers growing opium poppies and coca, and $93 million for "expanding the rule of law." Since taking office, Pastrana has enjoyed clear support from the Clinton administration even while his domestic approval ratings have tumbled.

"U.S. aid in and of itself cannot help Pastrana," said Alfredo Rangel, an adviser to former president Ernesto Samper. "The president needs to change the country's expectations with regards to the economy and the peace talks."