WASHINGTON - Some of the first information gleaned from material found at Osama bin Laden's compound indicates al-Qaida considered attacking US trains on the 10th anniversary of the September 11 attacks, but counterterrorism officials say they believe the plot was only aspirational and have no recent intelligence about any active plan for such an attack.

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As of February 2010, the terror organization was considering tampering with an unspecified US rail track so that a train would fall off the track at a valley or a bridge, according to a Homeland Security intelligence warning sent to law enforcement officials around the country Thursday. The warning, marked for "official use only," was obtained by The Associated Press.

This information appears to be the first widely circulated intelligence pulled from the raid this week on bin Laden's secret compound in Pakistan. After killing the terror leader and four of his associates, Navy SEALs confiscated a treasure-trove of computers, DVDs and documents from the home where he had been hiding for six years.

Intelligence analysts have been reviewing and translating the material, looking for information about pending plots and other terror connections.

"We want to stress that this alleged al-Qaida plotting is based on initial reporting, which is often misleading or inaccurate and subject to change," Homeland spokesman Matt Chandler said. The government has no plans to issue an official terror alert, he said.

"While it is clear there was some level of planning, we have no recent information to indicate an active ongoing plot to target transportation and no information on possible locations or specific targets," the May 5 warning said.

US officials have disrupted other terror plans that targeted rails, including a 2009 plot to blow up the New York City subway system.

On Monday the FBI and Homeland Security warned law enforcers around the country that bin Laden's death could inspire retaliatory attacks in the US They said the transportation sector, including US rails, remain attractive targets.