New York prepares for Mumbai-style attack

The drill on Thursday simulated an attack in lower Manhattan's financial district, near Wall Street and Ground Zero, on a mock block that contained a department store, a hotel and a federal regulatory agency, according to ABC News.

European authorities view these as the kind of "soft" and financial targets that might be attacked in a commando-style assault. Multiple civilians and officers were "shot" during the drill.

"We've got some info from one of the perps (slang for one who perpetrates a crime) that the Empire State Building might be next," one police radio crackled during the drill. As it did, helmeted cops with M4 rifles and M14 assault rifles began stalking the street hunting snipers and assailants.

"What we try to do is stress the system," New York Police Commissioner Ray Kelly said. "We think the unthinkable."

Thursday's exercise that simulated multiple bombs and shooters, including a bomb under a vehicle, and police responded with helicopters, dogs, automatic weapons and an armoured car, was the ninth since Mumbai.

Earlier Thursday, the State Department's counterterror chief told reports in London that the travel alert issued last week that advised travellers in Europe to be careful was still in effect. "We don't view the conditions as warranting us rescinding the alert," said Daniel Benjamin.

The alert was issued Oct 3, when intelligence led authorities to believe a Mumbai-style assault on so-called "soft" civilian targets might be imminent in Europe.

European and US authorities first learned of the plot over the summer following the capture of Ahmed Siddiqui, a suspected German terrorist who had been training in Pakistan.

Recent law enforcement operations within the United States have helped to flush out chatter that added to earlier concerns about the US homeland as a possible additional target of the attacks, ABC said.

Known targets are believed to include England, France and Germany. Additional European countries, including Italy and Belgium, are also targets, it said citing multiple sources.

Siddiqui's claims about a multi-city plot against Europe have been bolstered by other "highly reliable" sources of information, US and German intelligence officials said Thursday.

They told ABCNews.com that about 45 other "potentially dangerous" individuals in Germany are being tracked as officials seek to prevent an attack from taking place.