India and the US signed a foundational defence partnership agreement on Thursday, signalling the deepening of a relationship that has warmed over the past few months, with the Americans previously allowing India to import key defence equipment and technologies, even creating a mechanism for a waiver for the country from a law that effectively prohibits arms imports from Russia, and the two countries moving closer to a rapprochement on the trade front. The Communications Compatibility and Security Agreement (Comcasa) was signed by India and the United States on Thursday at the inaugural two-plus-two dialogue between their foreign and defence ministers. The two countries also agreed on several other measures to step up defence and security ties.Comcasa, delayed for years as New Delhi bargained hard for getting its concerns addressed before inking the sensitive pact that would effectively mean opening up its military communications network to the US military, comes into force with immediate effect and will be valid for 10 years. The India-specific Comcasa has in-built safeguards to secure India’s national interests with complete access to equipment to make sure there is no disruption, said two officials familiar with the details of the agreement.One of the officials cited above said on condition of anonymity that it was an enabling agreement and did not commit India to future military acquisitions from the US. He also added that Indian military data could not be shared by the US with a third party without consent.The agreement was signed after external affairs minister Sushma Swaraj and defence minister Nirmala Sitharaman held three sessions of talks with their US counterparts, US secretary of state Mike Pompeo and defence secretary Jim Mattis.Comcasa aims to give a legal framework for the transfer of highly sensitive communication security equipment from the US to India that will streamline and facilitate interoperability between their armed forces. It is one of the three foundational agreements for a seamless military relationship between the two sides. India had signed the Logistics Exchange Memorandum of Agreement (LEMOA) in August 2016. Customised for India again, this agreement gives the two countries access to named military infrastructure in the other country for logistics support including refuelling. The third agreement is the Basic Exchange and Cooperation Agreement for Geo-spatial Cooperation (BECA) , which, once signed, will allow the US to share sensitive data with India. Work is yet to begin on the third agreement. “The (leaders) welcomed the signing of a Communications Compatibility and Security Agreement (COMCASA) that will facilitate access to advanced defence systems and enable India to optimally utilise its existing US-origin platforms,” read a joint statement issued after the meeting.“Defence cooperation has emerged as the most significant dimension of our bilateral relationship,” Sitharaman said, summing up the mood after two sides also agreed to hold the first tri-services exercises next year, and announced that they would begin negotiations on an “Industrial Security Annex (ISA)” that would support a closer cooperation and collaboration between their defence industries.Strategic affairs expert C Uday Bhaskar said the signing of Comcasa was a “significant punctuation in the bilateral defence cooperation framework.”“This protocol has immediate operational implications, being able to exploit the US-supplied platforms to optimum capability and long-term possibilities by way of technology cooperation or perhaps transfer. It is instructive to recall that the first defence cooperation agreement was signed in June 2005 and it has taken India 13-plus years to reach this stage. Team Modi is to be commended for overcoming the political diffidence of early years.”Pompeo described Comcasa as a “major step” forward.The joint statement amply reflected the growing synergy in defence ties between the two countries.“Recognising their rapidly growing military-to-military ties, the two sides committed to the creation of a new tri-services exercise and to further increase personnel exchanges between the two militaries and defence organisations”, the joint statement said.The ministers reviewed the recent growth of bilateral engagements in support of maritime security and maritime domain awareness, and in a bid to expand maritime cooperation in the western Indian Ocean, agreed to start exchanges between the US Naval Forces Central Command (Navcent) and the Indian Navy. “The momentum in our defence partnership has imbued a tremendous positive energy that has elevated India-US relations to unprecedented heights,” Sitharaman said. Though Russia remains the biggest defence partner of India, the US has become India’s second-largest arms supplier; the two countries have closed $15 billion worth of deals in the last decade. The meeting also saw the two sides agreeing to step up their counter terrorism cooperation.External affairs minister Sushma Swaraj termed the growing trade and investment ties as an important element of bilateral relationship. “This growth is giving rise to new opportunities and a basis for more intense economic engagement which supports development of manufacturing, promotes knowledge and innovation, creates jobs and provides critical resources for growth”. Swaraj also made a strong pitch to address visa issues. “I sought Secretary Pompeo’s support to nurture our people-to-people links. Specifically, I conveyed our expectation for a non-discriminatory and predictable approach to the H1B visa regime, given its high impact on innovation, competitiveness and people-to-people partnership, all of which are a vital source of strength for our relationship,” Swaraj said.The two sides agreed to set up a hotline between the external affairs minister and the secretary of state.India and the US also discussed the Indo-Pacific, where China’s footprint is growing. “We see the Indo-Pacific as a free, open and inclusive concept, with ASEAN centrality at the core and defined by a common rules-based order that both our countries are pursuing,” Swaraj said, adding that India welcomed the US’s interest in expanding its economic footprint in the region as they “complement our own efforts”.The two sides have agreed to deepen ties in international forums such as the United Nations and the Financial Action Task Force. They also discussed the ongoing efforts by India and the US in promoting an Afghan-led, Afghan-owned and Afghan government-controlled reconciliation process. The US will host the next edition of the dialogue. Some experts said India hasn’t got as much as the US has from the agreement. “The US side got what it wanted -- India’s signature on Comcasa. But what did India get? Trump’s Iran sanctions and other actions have increased India’s oil-import bill and depreciated the rupee,” said strategic affairs expert Brahma Chellany.His reference is to US sanctions on imports from Iran -- an important oil supplier to India. Indian officials were hoping to discuss the issue during the two-plus-two dialogue. While it didn’t figure in the statement, the two countries did discuss the issue.