WASHINGTON - The US has no reason to believe Pakistan's government was involved in last week's terrorist attacks in Mumbai, and the Bush administration trusts Pakistan to investigate the issue, White House spokeswoman Dana Perino said Monday. "We have no reason not to" trust Pakistan "right now," Ms. Perino told reporters at a briefing. "I've heard nothing that says the Pakistani government was involved." President George W Bush is sending Secretary of State Condoleezza Rice to India in an effort to defuse the rising tensions betwen India and Pakistan in the wake of the terrorist strikes in Mumbai. Dr. Rice is scheduled to arrive in New Delhi on Dec. 3 after attending a NATO meeting in Europe. Ms Perino said that the intelligence community is "still assessing all aspects of the attacks, the motivation, the plotting and planning, and the operational details of it." Bush called Indian Prime Minister Manmohan Singh Sunday, assuring him that the US "stands in solidarity" with his country, according to Gordon Johndroe, a spokesman with the National Security Council. Bush told Singh that he has instructed the state and defense departments "to devote the necessary resources and personnel to this situation," Johndroe said in an e-mailed statement. The president told Singh "that he believes out of this tragedy can come an opportunity to hold these extremists accountable and demonstrate the world's shared commitment to combat terrorism," Johndroe said. On Monday, Ms. Perino welcomed Pakistan's pledge to cooperate in the investigation as a "good and positive step", saying, "I have heard nothing that says that the Pakistani government was involved." The spokeswoman said the top US leadership has been in contact with the top Pakistani leaders who have said they would work with the Indian government. "We have been encouraged by the statements by the Pakistanis that they are committed to following whatever leads, we expect nothing less of them on this incident," she added. "We have no reason not to (trust) right now. Everything they have said in their public statements and private statements has been encouraging from that regard. Remember Pakistan has been the victim of terrorism as well. It's not even a year since Benazir Bhutto was assassinated by a terrorist and so it is a fresh wound for them as well." On reducing tensions in the region, the spokeswoman said Washington has encouraged India and Pakistan to open channels of communication. "We have encouraged them to open that line of communication and Indians have gotten some responses from the Pakistanis that they are committed to following through on this investigation. That is a good and positive step. We need to continue to make sure that that helps," she said in reply to a question. In response to another question, Ms. Perino said the US has been consistently encouraging "India and Pakistan to increase their cooperation and dialogue, we have been working on the composite dialogue, we have provided technical assistance in order to support confidence building measures between the two countries, and we will continue to do that." She said "India has been a victim of terrorist attacks before and so has Pakistan." But in the Mumbai attacks six Americans have been killed, she added, pointing out the difference. "You remember the terrorist attacks on the parliament building (in New Delhi) several years ago that fostered a lot of tension between Pakistan and India as well, they have been able to have cooperative conversations, even though they might be tense. That is the kind of diplomatic solution that we are trying to foster here." "Obviously, we want to have reduced tensions wherever possible, the good news is the Pakistanis and the Indians have open lines of communication. This is something they did not have just even a few years ago. "We have encouraged them to open that line of communication and Indians have gotten some responses from the Pakistanis that they are committed to following through on this investigation. That is a good and positive step. We need to continue to make sure that that helps" "One of the reasons for Secretary Rice's travel to India is not only to show solidarity with India but also to stop the terrorist threat from expanding. It is a stark reminder that we are at war with ideological extremists, who kill innocent people in spectacular ways in order to advance their agenda." Ms. Perino said the other thing the attacks show is that "we are right to go on the offense to prosecute this war. We have to be fighting them and we have to be right a hundred per cent of the time, they just have to be right once." Asif Mehmood from London adds: US Secretary of State Rice called on Pakistan to show "absolute" cooperation and "total transparency" with India in the investigation of who was behind the Mumbai attacks. "I don't want to jump to any conclusions myself on this, but I do think that this is the time for a complete, absolute, total transparency and cooperation and that is what we expect," she told reporters accompanying her. She said, "It is extremely important that there would be the highest levels of cooperation between Pakistan and India at this point and that means all institutions", she added. "And I assume that there is going to be a law enforcement cooperation as well as intelligence cooperation in getting to the bottom of this," she said, before arriving in London. "What we are emphasising to the Pakistani government is the need to follow the evidence wherever it leads and to do so in the most committed and firmest possible way." she maintained. AFP adds: she declined to comment on reports that Pakistan-based Lashkar-e-Taiba could be behind the deadly attacks.