The attackers had broad international contacts, Britain's spy chief, MI5 Director General Jonathan Evans, said in newspaper interviews published on Wednesday.

"We have looked at individuals' communications, where they have been and so on and found they have got connections with most countries including the UK, but not of national security significance," London's Daily Telegraph quoted him as saying.

Wainstein declined to discuss whether there was any sign the attackers communicated with people in the United States.

The attacks in Mumbai may spark more such raids by militants now that defenses are improving against suicide car-bomb attacks, Dell Dailey, the US State Department's counterterrorism coordinator, said on Tuesday.

"This might open the door of awareness," he told reporters, as Evans made similar comments in London. "The spectacularness of an on-foot attack will unfortunately ring true to other terrorist organizations," Dailey said.

Wainstein said early lessons from Mumbai underscored a need for facilities such as hotels to be told of intelligence on potential threats, and to take them seriously. He said the public also must be made aware of such threats.