LONDON — The United States has told Pakistan it expects complete cooperation in connection with investigations into the terrorist rampage in nuclear rival India, Secretary of State Condoleezza Rice said today, saying the civilized world must unite against this global menace.

Appearing at a news conference with British Foreign Secretary David Mililand, Rice said the perpetrators of attacks that have taken the lives of at least 170 in Mumbai, India, "must be brought to justice." She also said Pakistan's response to the attacks will be a test of the will of the new civilian government.

"What we are emphasizing to the Pakistani government is the need to follow the evidence wherever it leads," Rice said. "I don't want to jump to any conclusions myself on this, but I do think that this is a time for complete, absolute, total transparency and cooperation and that's what we expect."

At President George W. Bush's direction, Rice is cutting short a European trip to visit India later this week. Six Americans were among those killed in attacks spanning three days in the Indian commercial capital Mumbai.

Rice said that "ultimately, the terrorists have to be stopped because they will keep trying to bring down" civilized nations and institutions.

"It was also a terrible day for the United States and for Great Britain," and other countries who lost people in the attacks, Rice said. "In the case of Great Britain and the United States, these were peole who were singled out because they were British and because they were American and that gives this a qualitatively different character from the point of view, certainly, of President Bush and, as I understand it the British government."

Indian leaders have pointed fingers at "elements in Pakistan" although it is not yet clear where the well-planned operation originated.

Attackers chose sites representing the city's wealth and tourism, and reportedly sought out Westerners as victims. Rice will see Indian leaders in New Delhi. She does not plan to go to Mumbai.

A previously unknown Muslim group called Deccan Mujahideen — a name suggesting origins inside India — has claimed responsibility for the attacks. But a top Indian police officer said Sunday he believed the attackers were from Lashkar-e-Taiba, long seen as a creation of the Pakistani intelligence service to help fight India in the disputed Kashmir region. The group was banned in Pakistan in 2002 under pressure from the U.S., a year after Washington and Britain listed it a terrorist organization.

Bush was in the Situation Room Monday morning, getting another update on the terrorist attacks.

Pressed about what the White House knows of the terrorists' motives, press secretary Dana Perino said: "The intelligence community is still assessing all aspects of the attack, the motivation, the plotting and planning and the operational details of it."

Asked if she was convinced that there was no Pakistani government role in the attacks, "I'm not going to comment on any possible involvement. ... I've heard nothing that says the Pakistani government was involved."

Later, Perino added the White House has "no reason" not to trust the Pakistanis. Perino noted that Pakistan, too, has been the victim of horrific terrorist attacks.

As for Americans' safety, Perino said "We do believe that all the American citizens are accounted for at this point."

Indian leaders have blamed unspecified "elements in Pakistan" for the 60-hour siege during which suspected Muslim militants hit 10 sites across Mumbai, but have not said whether they believe the terrorists had the backing of any state agencies. Pakistan denied it was involved and demanded evidence.

India has repeatedly accused Pakistan of complicity in terrorist attacks on its soil, many of which it traces to militant groups fighting Indian rule in Kashmir. The U.S. has tried to persuade Pakistan to shift its security focus from India, with which it has fought three wars, to Islamic militants along the Afghan border.

For her part, Perino said Monday that the United States will Pakistan to its promise of cooperation.

Asked if the Bush administration trusts the Pakistani government to fully investigate the attacks, Perino said, "We have no reason not to right now. Everything that they have said in their public statements and in their private statements have been encouraging in that regard."

She said it's a very serious situation that has fostered a lot of tension in the region.

"We're asking everyone to reduce the rhetoric, reduce the tensions and cooperate on an investigation," Perino said.

"In some ways, that whole region is like a forest that hasn't had rain in many months and one spark could cause a big, roaring fire. That's what we're trying to avoid," she said.

Perino also said that "the tension between Pakistan and India have been around for decades, and we have been trying to encourage and improve dialogue between the two countries."

"It's a very serious situation and there's no doubt that there's a lot of tension."