From diplomatic drama in Beijing to fiery Indian politics - U.S. secretary of state Hillary Clinton arrives in Kolkata in West Bengal state on a three-day India trip.

Clinton is due to meet West Bengal's outspoken but influential chief minister, Mamata Banerjee, before travelling to New Delhi for talks with Indian prime minister Manmohan Singh.

High on the agenda for the meeting with Banerjee is likely to be the issue of retail reform.

The U.S. is pushing for India to open its supermarket sector to foreign chains such as U.S. giant Walmart - a policy fiercely opposed by Banerjee, amongst others .

In New Delhi, Clinton will be seeking assurance that India will reduce its purchases of oil from sanctions-hit Iran.

Earlier, Clinton was in Bangladesh for a warm meeting with Nobel Laureate and Grameen Bank founder Mohamed Yunus and community activist Fazle Abed.

Clinton, a staunch defender of Grameen, pledged her full backing for Yunus and the pioneering micro-lending bank.

While the U.S. is keen to strenghten ties with Bangladesh, Clinton's visit coincided with the country's worst political crisis in years amid growing tensions over the disappearance of an opposition leader.

Clinton is the first senior U.S. official to visit Bangladesh since 2004.

Sunita Rappai, Reuters