Washington ? The FBI is advising law enforcement agencies to be on the lookout for terrorists who possibly are plotting to use fuel tankers to attack Jewish neighborhoods and synagogues, a federal law enforcement official said Friday.

This official, who asked not to be identified, said the warning was sent out to local police agencies Friday.

Another official, also speaking on grounds of anonymity, said the warning was not based on a specific threat, but on interviews with captured al-Qaida and Taliban fighters who indicated such a plot had been discussed. The interviews with detainees did not reveal a target city or time, this official said.

“Even if unconfirmed, we analyze incoming information as quickly as possible and if we think there is any chance it could be helpful, we make the decision to send it,” one official said.

The official said the advisory was sent across the National Law Enforcement Telecommunications System, an electronic system that allows the FBI to send alerts or messages to police in all 50 states simultaneously.

The Homeland Security office approved the message before it was sent, according to the official. The FBI’s 56 field offices also were made aware of the advisory.

The FBI has initiated several nationwide efforts to disrupt possible terrorist plots in recent weeks.

FBI agents have been contacting hundreds of scuba diving shops out of concern the next wave of terrorist attacks could be carried out by divers.

The FBI said it is looking into whether al-Qaida operatives have been taking scuba training in order to blow up ships at anchor, power plants, bridges, depots or other waterfront targets.

Also, a maintenance worker who said he wanted to buy a replica ambulance for tool storage triggered an FBI warning in two states that terrorists might try to use emergency vehicles in an attack. After interviewing the man, the FBI found he had no such plan.

Law enforcement officials were contacted about two weeks ago, after two men walked into Movie Time Cars Inc., a company that rents replicas of ambulances and police cars to TV and film producers.