WASHINGTON (AP) -- Emboldened by their deadly success in Spain, terrorists could attempt to influence the U.S. election and shock the world by launching attacks during this year's presidential nominating conventions or at the Olympics in Greece, FBI Director Robert Mueller said Thursday.
"We understand that between now and the election, there is a window of time in which terrorists may well wish to influence events, whether it's in the United States or overseas," Mueller said in an interview with The Associated Press.
He also said that Islamic extremists are changing tactics to focus on recruitment of local sympathizers less likely to arouse suspicion than outsiders. And terrorist groups may well move away from fortified targets, such as airports and government buildings, he said.
"I do believe that when we enhance our security, harden targets, terrorists look for other targets that are soft targets," Mueller said. When new security measures are taken, he said, "the terrorists are thinking about ways to circumvent them."
The March 11 train bombings in Madrid that killed 190 were a factor in the ouster of Spain's government, and that has added to concern about the U.S. political conventions in New York and Boston this summer.
"In the wake of what happened in Madrid, we have to be concerned about the possibility of terrorists attempting to influence elections in the United States by committing a terrorist act," Mueller said. "Quite clearly, there will be substantial preparations for each of the conventions."
U.S. officials also are deeply concerned about security for the Athens Olympics in August. Mueller said he was awaiting a review of a recent anti-terrorism exercise to "see again what we could do if there are areas that need to be shored up."
Asked if security would be adequate by the time the Olympics begin, Mueller said: "It's premature to make any definitive judgment as to where we are in the stages of preparations."
Regarding new al-Qaida recruiting tactics, Mueller pointed to the May 16 suicide bombings in Casablanca, Morocco, as evidence of change. In those attacks, local Islamic extremists were recruited by outsiders probably linked to al-Qaida to carry out the mission.
"We, along with our counterparts, have to be alert to that type of combination of local persons as well as others who may have expertise in timing devices, and constructing (bombs), coming together with those who are willing to sacrifice themselves," Mueller said.