The U.S. State Department says despite President Hamid Karzai's commitment to fight opium-poppy cultivation, Afghanistan presents a daunting and long-term challenge in the fight against the illegal global drug trade. The department issued its annual report on narcotics control Wednesday.

The massive 930-page document, issued only hours after President Bush paid a surprise call on Mr. Karzai in Kabul, did not question the Afghan leader's commitment to battle narcotics.

But it said despite a 10 percent decline in output last year, Afghanistan remains the source of 90 percent of the world's opium poppy and that drug-related government corruption, and an insurgency, make the elimination of the problem a daunting and long-term task.

The report, mandated by an act of Congress, was released at a news conference by Assistant Secretary of State for International Narcotics and Law Enforcement Affairs Anne Patterson.

She acknowledged that opium output had increased since the fall of the Taleban, who she said had used draconian anti-drug methods that would not be acceptable for most civilized governments.

Patterson said with U.S. and British assistance, Afghanistan is about to embark on new efforts to curb poppy cultivation based on tactics including crop eradication that have proved effective elsewhere including Colombia.

But she said the task in Afghanistan will be far more difficult given the country's past three decades of disruption and civil conflict.

"I don't want to underestimate the difficulty of this, because Colombia is a paradise next to Afghanistan," she said. "This is going to take years and years and years. But it's important to do, not only because of the security of Afghanistan and Afghanistan's democratic institutions. It's also important to do because of the cheap heroin that's spreading into neighboring countries and Europe. So we're going to stick with this."

The assistant secretary said Iran has been a major victim of Afghan opium, with addiction levels rising despite interdiction efforts along its long border with Afghanistan.

The report had a generally-upbeat assessment of the situation in Colombia, though it remains the source of most of the illicit cocaine entering the United States.

It said 2005 had been a record year in Colombia for eradication, interdiction and extradition of suspected traffickers to the United States. Patterson said U.S.-supported anti-drug efforts by the Bogota government under its Plan Colombia have had the ancillary effect of reducing the country's serious crime problems.

"It's been a dramatic success I think in ways we didn't fully anticipate, which is to restore security in the country. As I mentioned, homicides are down, kidnappings are down. Kidnappings have a wildly disproportionate effect on foreign investment. The fact that they've been reduced so significantly means that Colombians will bring their money back, and foreign investors will come in," she said.

The report said Venezuela, hampered by rampant law-enforcement corruption and a weak judiciary, was increasingly becoming a transit point for drugs leaving Colombia - creating what Patterson described as a hole in our counter-narcotics strategy.

It said Bolivian production of coca, the base ingredient for cocaine, has begun to increase after years of major crop eradication progress.

Assistant Secretary Patterson said the United States wants to work closely with Bolivia's new president, Evo Morales, despite his past role as a coca-growers federation official and statements that he would like to legalize the crop.

She said senior State Department officials have met Mr. Morales several times to engage him on the issue but made no prediction about future cooperation, saying we'll just have to see how it goes.

The report said opium production in Burma was just a fraction of what it was a decade ago, but said traffickers continue to operate with seeming impunity in some tribal areas.

It credited Laos with unprecedented success against the opium trade and said it could cease to be a major producer in the near future.

The report did not spare U.S. allies and neighbors, saying large amounts of marijuana and synthetic drugs like methamphetamine arriving in the United States originated in Canada and Mexico.

It said illicit labs in Poland are turning out amphetamines for the European market, while saying that Dutch authorities had taken notable steps in 2005 to curb trade in the synthetic drug Ecstasy or MDMA.