US Secretary of State Hillary Rodham Clinton has promised to give full US support to Indian efforts to protect itself from terror attacks.
Her pledge Tuesday comes less than a week after a triple bombing killed 19 people in the financial capital of Mumbai.
The fight against terror, India's concerns over nuclear-armed rival Pakistan and US withdrawal plans for Afghanistan are expected to dominate talks throughout the day between Clinton and Indian officials in New Delhi.
At the start of a meeting with India's foreign minister, Clinton said: "We are allies in the fight against violent extremist networks. And homeland security is a high priority and a source of increasing partnership."
Meanwhile, Clinton also urged India to open markets faster and resolve questions on a civilian nuclear accord that US companies hope could mean billions of dollars in new business.
Clinton opened high-level US-Indian talks with a polite but firm push for New Delhi to get moving on key economic issues as both sides seek to firm up a relationship that thus far has promised more than it has delivered.
"The stakes are high. So it is critical that this dialogue lead to concrete and coordinated steps that each of our governments take to produce real results," Clinton said in her opening remarks at the meeting, the latest in a series of talks aimed at deepening political and economic ties between the United States and the world's second most populous country.
Clinton's visit will cover a range of bilateral issues including counter-terrorism cooperation, an issue thrown into stark relief by last week's Mumbai attacks.
She will brief Indian leaders on US plans to draw down troops in Afghanistan -- which New Delhi fears may mean a hasty US exit -- as well as on India's nuclear-armed rival Pakistan, where the halting battle against Islamic militants has spurred questions about Islamabad's true intentions.
Clinton did not mention Pakistan in her opening statements, but did underscore that Washington and New Delhi have a common challenge in confronting the threat of militant violence.
"We are allies in the fight against violent extremist networks. And homeland security is a high priority and a source of increasing partnership," Clinton said, pointing to a May summit between Indian and US security officials.
"The events in Mumbai have driven home how important it is that we get results," she said.
US officials say they are generally pleased with growing levels of security cooperation with India, which range from intelligence sharing on terror networks to joint efforts against maritime piracy.
But India has long been unhappy about what it perceives as Washington's resistance to sharing critical, real-time information on Islamic militants in Pakistan and Afghanistan that may be plotting to attack Indian targets.
Clinton highlighted hurdles that continue to hamper progress on economic ties, which US officials say should be growing faster and deeper given India's $1.6 trillion economy.
On top of the list is civilian nuclear cooperation, which despite a landmark 2008 accord has yet to overcome Indian legal and regulatory obstacles which could open the doors to US nuclear energy companies such as General Electric and Westinghouse, the US-based arm of Japan's Toshiba.
Earlier this month, New Delhi hinted that it could ban nuclear reactor purchases from countries refusing to sell sensitive nuclear technology to it after suppliers decided last month to tighten such trade against countries like India.
US officials want India to "tighten up" legislation to protect equipment makers from liability in case of nuclear accident, saying it is much more stringent than comparable laws in other countries. India is planning to spend some $150 billion on nuclear power, key to meet soaring energy demand.
"I look forward to the day when the computers of a school in Gujarat are powered by a reactor designed in America," Clinton said, referring to one of India's fast-growing states. "We need to resolve remaining issues so we can reap the rewards of a robust civil nuclear energy partnership."
Clinton will also meet Indian Finance Minister Pranab Mukherjee, and is expected to press him on promises to open domestic financial and insurance markets, as well as to permit "big box" retail operations which could open the country further to US sales giants such as Wal-mart.
Clinton made clear that arms sales, too, are part of the equation, saying India, seen as one of the world's biggest defence buyers in coming years, could further improve U.S. military cooperation by buying more U.S. weaponry.
The United States was disappointed when India rejected US bids for an $11 billion fighter aircraft contract in April, but still hopes US companies can benefit as New Delhi forges ahead with one of the world's biggest arms purchase programs.
"The United States expects to continue developing and selling the world's most competitive products," Clinton said.
"We view these sales as important on their own terms, but also as a means to facilitate the work that the Indian and American militaries can do together."