US authorities said on Monday they had captured a suspected Al Qaeda operative carrying out reconnaissance for an attack on the United States with a radioactive "dirty bomb".
Abdullah al Muhajir, born in New York as Jose Padilla, was detained by the Federal Bureau of Investigation in Chicago over a month ago, when he flew in from Pakistan on May 8.
He was held without being charged until being declared an "enemy combatant" by President George W Bush on Sunday, after which he was transferred to a naval brig in South Carolina, officials said.
"We have disrupted an unfolding terrorist plot to attack the United States by exploding a radioactive dirty bomb," Attorney General John Ashcroft said in Moscow, where he was meeting Russian officials.
In Washington a short time later, FBI Director Robert Mueller said the plot had not gotten past the planning stages.
Officials said Muhajir, a 31-year-old American, travelled to Pakistan and Afghanistan in 2001 and met senior Al Qaeda officials to discuss the plan.
The officials would not say whether the meetings took place before or after the September 11 attacks on New York and Washington.
A so-called dirty bomb involves exploding a conventional device wrapped in or laced with radioactive material. Ashcroft said such a bomb could cause mass deaths but radiation experts said it would be more likely to cause panic than injury.
Asked where the attack was targeted, Deputy Defence Secretary Paul Wolfowitz said Muhajir had indicated some knowledge of the Washington, DC area but noted it was not an actual plan.
"He was instructed to return to the United States to conduct reconnaissance operations for Al Qaeda," Wolfowitz told a news conference.
Another official, who spoke on condition of anonymity, said Muhajir was "probably" targeting the US capital.
Trained with the Enemy
Ashcroft said the government had "multiple, independent and corroborating sources" that Muhajir was closely associated with the Al Qaeda and was "involved in planning future terrorist attacks on innocent American civilians in the United States".
US officials knew Muhajir was on the airplane heading into Chicago O'Hare International Airport on May 8, where he was detained upon arrival.
Mueller, whose bureau has been under fire for failing to share information with other US intelligence agencies that might have prevented the September 11 attacks, said the Central Intelligence Agency played a key role leading up to the arrest.
After a 1991 arrest in Florida on a handgun-related charges, Padilla began referring to himself as Abdullah al Muhajir, officials said.
Muhajir, who has family in the US, was last in the country in 1998. After that he travelled mostly in West Asia, the officials said.
"While in Afghanistan and Pakistan, Muhajir trained with the enemy, including studying how to wire explosive devices and researching radiological dispersion devices," Ashcroft said.
"Al Qaeda officials knew that as a US citizen, holding a valid US passport, al Muhajir would be able to travel freely in the United States without drawing attention to himself."
Muhajir is being held by the defence department as an "enemy combatant", which under the rules of war allows him to be questioned without the usual protections afforded in the US judicial system, like having an attorney present. Officials have not ruled out lodging criminal charges against Muhajir later.
Bush has said American citizens would not be tried in military tribunals that were created after September 11 to try foreign terrorists outside the US court system.
Tell us what you think of this report