West Bengal Chief Minister Mamata Banerjee (L) shakes hands with US Secretary of State Hillary Clinton before a meeting in Calcutta, India
US Secretary of State Hillary Clinton has urged India to buy less oil from sanctions-hit Iran.
In Calcutta, she commended India for "working to lower purchases of Iranian oil" and hoped it would do more, reports the BBC.
India has been facing pressure to buy less Iranian oil amid sanctions against Iran over its nuclear programme, which Tehran says is for civilian purposes.
She added Pakistan should act against Hafiz Saeed, founder of the group blamed for the 2008 Mumbai attacks.
Ten Pakistani gunmen killed 165 people in a three-day rampage that targeted luxury hotels, a train station and a Jewish centre.
"[The] reason why India, China, Japan, etc who are primary purchasers of Iranian oil, are being asked to lower supply is to keep pressure on Iran," Mrs Clinton said on the first leg of her visit to India.
The US and its western partners suspect Iran of using its nuclear programme to develop the capacity to develop atomic weapons.
Tehran says the programme is solely for civilian purposes.
The US plans to implement a round of sanctions, starting on June 28, against banks based in countries that do not cut their oil imports from Iran.
She said other supplies of oil were available to India.
"Saudi Arabia and others are putting more oil into the market," she said.
"India understands the use of diplomacy to resolve this threat and is working towards lowering purchases of Iranian oil... We hope they will do even more. We believe this is part of India's role in the international community."
Mrs Clinton also urged Pakistan to do more to arrest militant leaders, including Hafiz Saeed, the founder of Lashkar-e-Taiba - the group blamed for the Mumbai attacks.
In April the US announced a $10m (£6.2m) bounty for information leading to his arrest.
"We're well aware that there has not yet been the steps taken by the Pakistani government to do what both India and the United States have repeatedly requested them they do," she said.
"And we're going to keep pushing that point. So it's a way of raising the visibility and pointing out to those who are associated with him that there is a cost for that."
Mrs Clinton also held a near hour-long meeting with the chief minister of the eastern state of West Bengal, Mamata Banerjee, in Calcutta, before leaving for Delhi to meet Prime Minister Manmohan Singh on Tuesday.
Mamata Banerjee Ms Banerjee is a key ally of the government in Delhi
Ms Banerjee was recently named one of Time magazine's 100 most influential people in the world.
Ahead of her visit, Mrs Clinton said that though there had been much progress in ties with India "there is more work to be done".
Ahead of the meeting, Mrs Clinton said she wanted to discuss foreign direct investment in multi-brand retail trade, something Ms Banerjee has opposed.
"The more open India becomes over time, the greater the rise in [the] standard of living and opportunity... But I also understand politics and how these decisions can be difficult," Mrs Clinton told the NDTV news channel.
"So I will raise [the] US desire to open markets to multi-brand retail. Enormous experience can be brought to India on supply chain management, on developing relationships with small producers. The benefits may not be immediately perceived."
Mrs Clinton's visit to India is the final stop on a three-nation tour which also took her to China and Bangladesh.