A secret US law enforcement report, prepared for the Department of Homeland Security, has warned that al Qaeda is planning a terror “spectacular” this summer.
US officials, ABC News channel said, have kept the information secret, and Homeland Security Secretary Michael Chertoff told the network that the United States did not have “have any specific credible evidence that there’s an attack focused on the United States at this point”.
As British police investigated two failed car bombs in London and a fiery attack on Glasgow’s airport by a fuel-filled vehicle, US officials tightened security at transport hubs without raising the country’s overall alert level.
“We do not currently have any specific threat information that is credible about a particular attack on the United States,” Mr Chertoff told Fox News.
ABC News, quoting a senior US official, said on Sunday a secret law enforcement report prepared for the Department of Homeland Security warned that al Qaeda planned to carry out a spectacular attack this summer.
“This is reminiscent of the warnings and intelligence we were getting in the summer of 2001,” ABC quoted the unidentified official as saying.
The United States has been on heightened alert since the September 11, 2001, attacks by al Qaeda using hijacked airliners.
Further attacks
“Al Qaeda and its affiliates do intend to carry out further attacks against the United States and the West,” Mr Chertoff said.
“We also know that they tend to want to do attacks that are spectacular or high-profile, so it’s not surprising to have analysts comment on the fact that this kind of an attack is a very definite possibility,” he said.
“But again I want to say that’s more general analysis that is not based on a specific piece of information about a particular attack.”
Mr Chertoff had made similar comments in interviews on Sunday about the possibility of a specific security threat to the United States.
British authorities have linked the three incidents late last week to al  Qaeda and detained seven people as part of an investigation.
“I wouldn’t rule al Qaeda out,” Mr Chertoff said.
“We have seen, however, different kinds of attacks. Sometimes, there are al Qaeda-affiliated groups that use different methods than what we might call core al Qaeda.”
The great lesson from the British plots, he said, was the two London attacks were foiled partly because people saw something suspicious and alerted the authorities.
“We are in very close contact with British authorities and have been since this whole episode began a few days ago,” Mr Chertoff said.
Earlier, ABC had reported that US law enforcement officials received intelligence two weeks ago warning of terror attacks in Glasgow and Prague, the Czech Republic, against “airport infrastructure and aircraft”.
The warnings apparently never reached officials in Scotland, who said they had received “no advance intelligence” that Glasgow might be a target, ABC said.
Unlike the United States, officials in Germany have publicly warned that the country could face a major attack this summer, also comparing the situation to the pre-9/11 summer of 2001, ABC noted.