NEW DELHI - Indian security forces fired tear gas to stop thousands of farmers demanding minimum crop prices from marching on the capital New Delhi after talks with the government failed.
Local broadcasters showed thick clouds of tear gas fired to disperse protesters near Ambala, some 200 kilometres north of the capital.
Police have set up a fearsome blockade of metal spikes, cement, and steel barricades on the highways from three surrounding states leading to the capital.
"Maximum numbers have been deployed," Ranjay Atrishya, assistant commissioner of Delhi Police, told AFP.
Public gatherings of more than five people have been banned in the capital.
Farmers in India have political heft due to their sheer numbers, and the threat of renewed protests comes ahead of national elections likely to begin in April.
Two-thirds of India's 1.4 billion people draw their livelihood from agriculture, accounting for nearly a fifth of the country's GDP, according to government figures.
Indian broadcasters showed columns of hundreds of tractors moving towards the capital from the surrounding states of Punjab, Haryana and Uttar Pradesh.
An AFP photographer saw police close roads at Ghazipur on the outskirts of Delhi, using multiple lines of blockades. A first line of defence using razor wire was set up, then metal barriers, concrete blocks and finally police buses.
The farmers are demanding a law to fix a minimum price for their crops, besides a clutch of other concessions including waiving off loans.