A warm handshake between India's Prime Minister Manmohan Singh and Russian president Vladimir Putin in New Delhi on Monday.

Putin - on his first trip to India since he started a new six-year term in May - is expected to talk arm sales with his long-standing regional ally.

Russian defence sources say the visit could produce deals worth more than $7.5 billion, including fighter jet and aircraft engine sales.

India plans to spend about $100 billion over the next 10 years to uprade its largely Soviet-era military equipment.

Meanwhile, security was tightened in New Delhi, and roads and metro stations shut as anti-rape protests intensified in the capital.

Publc outrage over the vicious gang rape of a 23-year-old stuident in a bus just over a week ago has resulted in several pitched battles between the police and protesters.

The protests have been the biggest in the capital since last year's demonstrations against corruption.