US President Barack Obama has arrived in India for a three-day visit amid an unprecedented security operation.
Thousands of security personnel have been deployed in Delhi along with some 15,000 cameras.
PM Narendra Modi stressed the importance of the visit by breaking protocol to receive Mr Obama personally at Delhi airport.
Their talks will primarily focus on trade, but also take in security, nuclear power and climate change.
Mr Obama will also be the guest of honour at Monday's Republic Day celebrations.
'Great honour'
After his arrival, the US president travelled to the presidential palace, Rashtrapati Bhavan, for an official welcoming ceremony with his Indian counterpart Pranab Mukherjee.
Mr Obama said: "This is a great honour, we are grateful for this extraordinary hospitality."
