U.S. officials announced yesterday that they had foiled two separate plots to use drug money to buy weapons for terrorists, including an alleged attempt by a U.S. citizen and two Pakistanis to swap tons of heroin and hashish for Stinger missiles that they planned to sell to al Qaeda.

In the second case, Justice Department officials said they had broken up a plot by right-wing Colombian paramilitaries to buy $25 million worth of high-powered East European weaponry with cocaine and cash.

The cases illustrate the increasingly aggressive efforts by U.S. authorities to stanch the flow of drug money and other funds that terrorists use to buy weapons and finance their activities. From Islamic militants to Colombian paramilitaries, Attorney General John D. Ashcroft said, there is a "deadly nexus between terrorism and drug trafficking" that poses a serious threat to American security.

"We have learned, and we have demonstrated, that drug traffickers and terrorists work out of the same jungle; they plan in the same cave and they train in the same desert," Asa Hutchinson, head of the Drug Enforcement Administration (DEA), said at a Washington news conference with Ashcroft, FBI Director Robert S. Mueller III and other officials yesterday.

In both cases, authorities lodged the federal charge of providing material support to terrorist groups, a statute that has become the centerpiece of the Justice Department's domestic war on terrorism. The charge, used rarely before the Sept. 11, 2001, attacks, has been filed against defendants including John Walker Lindh -- who pleaded guilty to aiding the Taliban -- and the alleged members of al Qaeda sleeper cells in Lackawanna, N.Y., Portland, Ore., Detroit and Seattle.

According to a federal indictment unsealed in San Diego yesterday, the two Pakistani nationals and a naturalized U.S. citizen, who has lived in Minneapolis, were indicted on Oct. 30 for allegedly offering to trade 5 metric tons of hashish and 600 kilograms of heroin with undercover FBI agents for four Stinger missiles.

As the deal progressed, according to the indictment, the men told the agents meeting with them in Hong Kong that "they intended to sell the 'Stinger' anti-aircraft missiles . . . to members of the Taliban, an organization which the defendants indicated was the same as al Qaeda." The meetings with the men were taped, according to Ashcroft.

Syed Mustajab Shah and Muhammed Abid Afridi, both from Pakistan, and Ilyas Ali, a naturalized U.S. citizen from India, were arrested after that Sept. 20 meeting. They appeared in a Hong Kong court on Tuesday to fight extradition to the United States, officials said.

The Colombia case, called "Operation White Terror," began 13 months ago and resulted in videotapes and audiotapes of meetings with undercover FBI and DEA agents in London, Panama City and the Virgin Islands, where four suspects allegedly discussed exchanging drugs for weapons.

The arms were intended for the Autodefensas Unidas de Colombia, or AUC, a brutal umbrella group of paramilitary forces that has been blamed for hundreds of assassinations, kidnappings and massacres. It was labeled a terrorist organization by the State Department in September 2001.

U.S. authorities said the four suspects believed they were going to trade $25 million in cash and cocaine for weapons, including shoulder-fired antiaircraft missiles; 9,000 assault rifles; grenade launchers and nearly 300,000 grenades; 300 pistols; and about 53 million rounds of ammunition.

The sting included a bogus "PowerPoint" computer presentation given to AUC representatives that showed the weaponry. Later on, in April, U.S. agents allowed one of the prospective buyers to inspect samples of the weapons during a meeting in St. Croix, according to court documents.

Four men were charged in the case: Carlos Ali Romero Varela and Uwe Jensen, both of Houston, and Colombian nationals Cesar Lopez, also known as Commandant Napo, and an unnamed defendant known only as "Commandant Emilio." The four were charged in federal court in Houston with conspiracy to distribute cocaine and conspiracy to provide material support and resources to a foreign terrorist organization -- offenses punishable by as much as life in prison.

Jensen was arrested on Tuesday in Houston. He said during a federal court appearance yesterday that he is Danish but with U.S. citizenship. The three others were arrested on Tuesday in San Jose, Costa Rica, after traveling there to finalize the deal with U.S. undercover agents. They face extradition to the United States.

The AUC has long been named by advocacy groups as the worst perpetrator of human rights abuses in Colombia, including carrying out executions and other operations against leftist guerilla groups at the behest of the Colombian army.

In separate moves earlier this year, Ashcroft announced indictments against members of both the right-wing AUC and the leftist guerrilla group FARC, or the Revolutionary Armed Forces of Colombia.

U.S. investigators have said since Sept. 11, 2001, that they have uncovered several schemes by terrorist associates to raise money through drug sales. "Drugs are the currency of terrorists," said U.S. Attorney Michael Shelby of Houston, who was at yesterday's news conference. "This is the medium of terrorism in the 21st century."

In the largest recent case, dubbed Operation Mountain Express, participants in a massive methamphetamine ring allegedly sent millions of dollars to the Hezbollah terror organization. About 100 people were arrested in 10 cities in January as a result of the probe, which also found evidence of close ties between Mexican drug-trafficking organizations and Arab American organized crime groups in New York, Michigan and Canada.

Attorney General John D. Ashcroft -- with FBI Director Robert S. Mueller III, left, and DEA Administrator Asa Hutchinson -- announces arrests in a drugs-for-weapons investigation. Ashcroft noted that there is a "deadly nexus between terrorism and drug trafficking."