Advertising Resilient rebels. Rebounding drug crops. Rogue US soldiers snared in plots to smuggle cocaine and funnel stolen ammunition to paramilitary death squads.

The bad news has been piling up fast, almost five years after the US began doling out US$3 billion under its Plan Colombia aid program to wipe out cocaine and heroin production and crush a long-running leftist insurgency.

The setbacks show US efforts to help restore peace and the rule of law to this Andean nation face huge challenges. But Washington's top diplomat here is unfazed, saying the mission to grind down the rebels and deprive them of their finances from drug-trafficking will proceed.

In a conversation at his guarded residence, US Ambassador William Wood said the efforts must persist if Colombia's rebels, who have been at war in Colombia for 40 years, are ever to be defeated.

"In Colombia, terrorism without narcotics is a much more vulnerable target," Wood told reporters. Rebels control a large share of the drug trade in Colombia, which produces most of the world's cocaine and much of its heroin.

"If you take away drugs, you reduce incentive, the power to corrupt, the ability to buy weapons," Wood said.

Not buying it

But criticism of the costly effort is mounting.

John Walsh, a senior associate at the Washington Office on Latin America think tank, said recently that "the drug war is failing to achieve its most basic objectives."

In an editorial this week, the Pittsburgh Post-Gazette said Colombia "has turned into a sinkhole of money and military resources over the past five years."

"The Congress should scrap Plan Colombia now, rather than throw more good money after bad," the newspaper said, pointing out that availability of Colombian cocaine and heroin on US streets appears undiminished.

The Monitor, a daily in McAllen, Texas, said in a recent editorial that the drug war is "a demonstrated failure," and argued in favor of legalizing drugs.

Bad developments

Among recent events that have cast a shadow on US efforts in Colombia:

-- On Wednesday, Colombian police announced the arrest of two US Army soldiers for allegedly attempting to sell thousands of rounds of stolen US ammunition to right-wing paramilitary death squads. They are in custody of US officials and face court-martial in the US.

-- In April, rebels of the Revolutionary Armed Forces of Colombia, or FARC, launched an offensive in the Andes Mountains of southwest Colombia. It followed a string of rebel attacks across Colombia that killed dozens of Colombian troops.

"The intensity of the attacks are clearly a concern," Wood said.

-- In March, five US soldiers in Colombia were accused of smuggling cocaine to the US aboard a US military plane. They were whisked off to the US, where they were arrested. Some Colombian lawmakers called for their extradition to Colombia.

-- The White House reported in March that, despite a massive aerial fumigation offensive against cocaine-producing plantations last year, coca cultivation increased slightly to 113,847 hectares as farmers quickly replanted. Critics said the report showed the US was losing the war on drugs.

Additional request

Meanwhile, the Bush administration is seeking more than US$700 million from Congress in counterinsurgency and counternarcotics aid for Colombia for fiscal year 2006.

"There is no sign that in FY 2006 that we're going to take a cut," Wood said, relaxing near a crackling fire in the mansion that serves as his official residence.