US transit systems terror alert

       Counterterrorism officials are warning US mass transit systems around the nation to step up patrols because of fears an Afghanistan-born immigrant under arrest in Colorado may have been plotting with others to detonate backpack bombs aboard New York City trains.
       Investigators say Najibullah Zazi, a 24-year-old shuttle van driver at the Denver airport, played a direct role in a terror plot that unravelled during a trip to New York City around the anniversary of the Sept 11,2001 attacks. He made his first court appearance on Monday and remained behind bars.
       Mr Zazi and two other defendants have not been charged with any terrorism counts, only the relatively minor offence of lying to the government. But the case could grow to include more serious charges as the investigation proceeds.
       Mr Zazi has publicly denied being involved in a terror plot, and defence lawyer Arthur Folsom dismissed as "rumour" any notion that his client played a crucial role.
       The investigation into Mr Zazi's role and how many others may be involved was ongoing. Two law enforcement officials said late on Monday that more than a half-dozen individuals were being scrutinised in the alleged plot.
       The FBI said in a statement that "several individuals in the United States,Pakistan and elsewhere" were being investigated.
       Backpacks and cellphones were seized last week from apartments in Queens where Mr Zazi visited.
       In a bulletin issued on Friday, the FBI and Homeland Security Department warned that improvised explosive devices are the most common tactic to blow up railways and other mass transit systems overseas. And they noted incidents in which bombs were made with peroxide.
       In the bulletin, officials recommended that transit systems conduct random sweeps at terminals and stations and that law enforcement make random patrols and board some trains and buses.
       The effects of the warning were not immediately clear on Monday. New York's transit agency said it was in touch with an FBI-NYPD (New York Police Department) task force but wouldn't comment further.
       The task force feared Mr Zazi may have been involved in a potential plot involving hydrogen peroxide-based explosives, according to two law enforcement officials, who spoke on condition of anonymity.
       Investigators said they found notes on bomb-making instructions that appear to match Mr Zazi's handwriting,and discovered his fingerprints on materials - batteries and a scale that could be used to make explosives.He also made a trip to Pakistan last year in which he received al-Qaeda explosives and weapons training.
       A strange sequence of events began to unfold nearly two weeks ago when Mr Zazi, a legal resident of the US who immigrated in 1999, rented a car in Colorado and made a 2,560km trek across the heartland to New York. He said he went to New York to resolve an issue with a coffee cart he owned.
       He was briefly stopped entering the city as part of what was believed to be a routine drug check, and proceeded to his friend's place in Queens. Once there, his car was towed and authorities confiscated his computer. He was told by an NYPD informant that detectives were asking about him, and decided to cut the trip short and fly back to Colorado, authorities said.
       Officials speeded up the investigation and launched raids on several Queens apartments in a search for evidence of explosives.
       Since 2001, counterterrorism officials have shifted their approach and made the disruption of plots in their early stages a top priority.