The National Security Advisor Shivshankar Menon today said the access given by the US to the Pakistani-American terrorist David Headley was unprecendented. Speaking at a function in New Delhi Menon said such cooperation may not have been possible five years back. He said the level of engagement between our two countries is unprecedented. Menon said the visit of President Obama has given both the countries an opportunity to actually put into practice and not just to showcase what we actually practice.Asserting that he was very optimistic about the future of Indo-US ties, Menon said the best thing for the countries to do was to have a pragmatic approach in furthering the relationship.Former US Deputy Secretary of State, Strobe Talbott called for widening the bilateral economic partnership by using technological innovations. A high level business delegation is accompanying US President Obama to India to expand business partnership between the two countries. He urged both the countries to work together to address the pressing issue of climate change. Earlier, American officials said that transfer of high technology, issue of Visa's to I T professionals from India, Cooperation in Agriculture, Space Science, Health and Education will be the focus of discussion besides addressing the challange of Global Terrorism.