In a stern message to Pakistan, US President Barack Obama has said the safe havens of terrorism within that country are "not acceptable" and that those behind the Mumbai attack must face justice. Ahead of his visit here, Obama said the US will keep working with India for a future that delivers greater security, prosperity and dignity for all people. Asserting that his country has been unrelenting in its fight against terrorist groups, he said, "I've made it clear that even as the United States works with Pakistan to meet the threat of terrorism, safe havens within Pakistan are not acceptable and that those behind the Mumbai terrorist attack must face justice." His comment assumes significance as India has recently been having renewed questions over Pakistan's sincerity in ensuring punishment to the perpetrators of Mumbai attack of November 2008. The questions arose after the attack mastermind Zakiur Rehman Lakhvi was granted bail in the case. Obama noted that like Indians were tragically killed in the 9\/11 attack in New York, Americans were also killed in the 26\/11 attack in Mumbai. To send a strong message to the Indian people that "we stand together in defence of our security and our way of life", he had made Taj hotel in Mumbai his first stop during his first visit to India in 2010, he said in an e-mail interview to India Today. Upbeat about his upcoming three-day visit to India which he described as a "natural partner", Obama said he was proud to be the first US President to visit this country twice. He said he saw it as an opportunity to work with Prime Minister Narendra Modi to make concrete progress and to "hopefully begin a new era" in the history between our countries. Recalling his unveiling his vision during his last visit here, Obama said "While it's true that progress has not always come as fast as we would have liked, we've succeeded in deepening the US-India relationship across the board." The US President said Modi's election and his commitment to a new chapter in the relationship gives the two countries to further energise the partnership. "I'd like to think that the stars are aligned to finally realise the vision I outlined in Parliament (of India)". Noting that no two nations agree on everything, he said, "so of course, sometimes India and the United States will disagree. But I believe that we can work through any differences in a spirit of mutual respect". He said, "When those of us at the leadership level agree on action, our governments have to actually implement our decisions. We have to make sure our words are matched by deeds." The two countries can work together to reduce barriers to trade, investment, and high-tech collaboration, he said, adding American companies are ready to help build the infrastructure that will be the catalyst for the next wave of Indian growth. He had special praise for Modi, saying "his remarkable life story - from tea-seller to Prime Minister - is a reflection of the determination of the Indian people to succeed." He added that Modi has a clear vision of big things that he wants India to achieve.