India on Friday welcomed Pakistan's admission that the Mumbai terrorist attacks were planned in part on its soil but pressed the government in Islamabad to "act effectively against the license that terrorist groups enjoy in its territory." The fuller Indian response was a signal of the opportunity and challenge that awaits Richard C. Holbrooke, the American special representative, who leaves Afghanistan for India on Sunday. Pakistan on Thursday announced it was holding six people in connection with the attacks, including one it described as the ringleader, and it hit the ball back into India's court by asking for more information, including how the attackers procured cellphone chips and the DNA samples of nine gunmen who were killed. The sole survivor, Ajmal Kasab, a Pakistani, remains in Indian custody. On Friday, the Indian foreign minister, Pranab Mukherjee, described Pakistan's announcement as "positive" and said India would "examine" its request for information. But he made it equally clear that it was not enough. "We will continue to review the situation, including Pakistan's responses, and will take further steps that we deem necessary in order to protect our people," Mr. Mukherjee said in Parliament. "The threat of terrorism from Pakistan has emerged as a global menace and cancer. The major onus of responsibility to eliminate this threat rests on the government of Pakistan." India's response reflects its own need to balance domestic pressures as national elections approach with the need to lower tensions with its rival and neighbor. The United States sees the heightened tensions between India and Pakistan as a potential stumbling block to its efforts to leverage Pakistani cooperation in quashing the Taliban along the Pakistan-Afghanistan border. However, with elections approaching in May, India's Congress Party-led coalition government is under political pressure to demonstrate that it can extract something tangible from Pakistan to protect its citizens from future attacks. "What we want to see is if Pakistan is still maintaining terrorist infrastructure," said Lalit Mansingh, a retired Indian diplomat. "We haven't seen that yet. There is still denial." Mr. Holbrooke, on arriving here, will most likely face Indian wariness about how the Obama administration deals with Pakistan. It stems partly from a long and storied distrust of the American alliance with Islamabad. But the Indian caution is all the more pronounced today because it wonders to what extent the United States will continue its robust support of the Pakistani military, which India sees as propping up jihadist organizations. The Indian national security adviser, M. K. Narayanan, in an interview last week, praised the United States for its support in the aftermath of the Mumbai attacks, but signaled that India expected more. "Few countries in recent memory have been so helpful, but I don't think they have been able to get Pakistan to do what we finally want: deliver criminals who were responsible," Mr. Narayanan said. "Perhaps there is still hope the United States will be able to prevail on the Pakistan government, and if not, whether there will be some penalties they are willing to impose on Pakistan, such as curbing the funding to the military, which would probably hurt them more than anything else." India is also worried that it could be nudged to negotiate peace with Pakistan, including on Kashmir, the nub of their 60-year-long dispute, and potentially to tamp down its extensive involvement in Afghanistan, which rankles Pakistan. None of these issues are likely to be answered during Mr. Holbrooke's first visit. But they signal how fraught relations can be between New Delhi and Washington even as their interests fundamentally converge: to shut down groups like Lashkar for the sake of both Indian and American security. Policy analysts here worry that the new White House will view India in a new way, one that Amitabh Mattoo, a professor of international relations at Jawaharlal Nehru University, called "more sophisticated, less benign." "You won't get the kind of carte blanche you got with the Bush administration," Mr. Mattoo went on. "I don't think the wow factor is going to be there." India has also made it clear that it does not intend to get roped into an American-led regional plan that includes making a deal on Kashmir. Mr. Mukherjee, the Indian foreign minister, said in a recent interview: "This is a problem of fighting against terror. One need not look at terror through the prism of Jammu and Kashmir." The State Department has said Mr. Holbrooke's mandate does not include Kashmir. In a report in January, however, the Asia Society warned that while the Obama administration would be wise not to mediate the dispute, it could not ignore Kashmir in its efforts to restore peace in the region. "No consideration of South Asia's regional stability can be contemplated without understanding the deep complexities of Kashmir," the report noted, adding that "no American approach to the region can be whole without a careful eye and appreciation of developments in Kashmir and their impact." Mr. Holbrooke served as chairman of the Asia Society at the time the report was published.