KOLKATA: US Secretary of State Hillary Clinton landed in India on Sunday with hopes of reinvigorating a relationship seen as losing steam despite efforts to bring the world's two largest democracies closer.

Clinton will be wading into a row over Iran, which is sending a trade delegation this week to New Delhi despite US threats to slap sanctions on countries that buy the Islamic republic's oil.

Clinton's final stop on a three-nation tour follows a tense visit to China defusing a crisis over a dissident and a stop in Bangladesh where she urged the country's polarised politicians to unite in the push for development.

The veteran politician arrived in the eastern Indian city of Kolkata, where she will tour monuments and meet citizens in her latest bid to use her personal popularity as a diplomatic tool.

Clinton said that she saw ample progress in relations with India, pointing to rising trade and cooperation in areas from education to clean energy.

“I think it's like any relationship -- there is progress in some areas that we are very heartened by, and there is more work to be done,” Clinton told reporters before her arrival.

“But that's the commitment that we make when we say to another country, we want to be your partner,” she said.

India has bristled at a US law that would impose sanctions on banks from countries that buy oil from Iran due to concerns over Iran's contested nuclear programme. Only EU nations and Japan have so far been given exemptions to the law which starts on June 28.

India has been reducing oil imports from Iran, but is highly dependent on foreign energy and has historically enjoyed friendly relations with Tehran.

T.P. Sreenivasan, a former Indian ambassador to the United Nations, said that expectations for the US-India relationship had not been met but that Clinton had the advantage of being considered a friend of New Delhi.

The visit “comes at a useful time as there is a certain amount of strain in relations that needs to be rectified,” he said.

“The relationship has lost momentum partly because... both are preoccupied with their own internal problems,” he said.