Protest at India-US air exercise

India and the US recently signed a 10-year defence deal

Hundreds of left-wing activists have protested against a US-India air exercise in India's West Bengal state.

Protesters converged on three airports and threatened to mobilise "millions" against the 12-day exercise - the longest between the two air forces.

The leftists oppose increased US-India military co-operation, saying it undermines India's independence.

Delhi on Friday pledged the exercises would start as planned on 7 November and said security would be stepped up.

'Cope India'

Hundreds of leftists vowed to paralyse the airports of Calcutta, Bagdogra and Kalaikunda.

"We will lay siege to Kalaikunda, where the exercises take place," said Anil Biswas, state organisation chief of the Communist Party of India (Marxist) that leads West Bengal's ruling leftist coalition.

"We are against air exercises with the United States. Such a move will also jeopardise our national security. Millions will rise in protests."

The BBC's Subir Bhaumik in Calcutta says the US air force will be flying in F-16 fighters from Misawa in Japan and the Indians will use fighters of both Russian and Western origin for the exercises, called "Cope India".

Indian Defence Minister Pranab Mukherjee said the exercises would go ahead without interruption.

"We have requested the state government to make the necessary security arrangements so that the exercise can take place."

Delhi had close ties with the Soviet Union during the Cold War but ties with the US have steadily improved in recent years.

Earlier this year, India and the US signed a 10-year agreement to strengthen defence ties.

The landmark agreement will help facilitate joint weapons production, co-operation on missile defence and the transfer of technology.

In July the nations agreed to increase co-operation on civilian nuclear energy programmes.