Thousands of farmers across India blocked roads on Saturday with makeshift tents, tractors, trucks and boulders to pressure the government to roll back agricultural reforms that have triggered months-long protests.

While the initial protests were started by rice and wheat growers from northern Indian who camped out on the outskirts of New Delhi, support for them has been growing especially in states not ruled by Prime Minister Narendra Modi's party.

The federal government has offered concessions to the farmers but refuses to repeal three laws passed last year that it says are crucial to bring new investment to the sector, which accounts for nearly 15 per cent of India's $2.9 trillion economy and about half its workforce.

Read: How Modi’s attempt to crush the farmers’ protest seems to have backfired

But farmers fear the reforms will leave them at the mercy of big corporate buyers, gradually ending the current practice of assured government purchases mainly for grain such as wheat and rice.

Saturday's three-hour “chakka jam”, or road blockade, started around noon except in New Delhi and a couple of neighbouring states.

“Today, the support of the whole society is with farmers,” Yogendra Yadav, a political activist who is one of the leaders of the farmers' movement, said on Twitter. “Victory is certain.”

On a highway near the capital, some farmers smoked hookah as songs played on a loudspeaker.

Farmers squatted on the road in the eastern state of Odisha and Karnataka in the south with flags and banners protesting against the laws, with some carrying placards urging the government not to treat them as enemies.

'Maximum restrain'

Tens of thousands of farmers have already been braving New Delhi's winter by sleeping in the open for months on national highways. Their protests have mostly been peaceful but a tractor rally on Jan 26 flared into turmoil as some farmers clashed with police.

Since then, authorities have shut down the mobile internet in parts of the national capital and heavily barricaded border roads to prevent protesters from coming into the city again.

“The rights to peaceful assembly & expression should be protected both offline & online,” the Office of the United Nations High Commissioner for Human Rights said on Twitter, calling on authorities and protesters to exercise “maximum restraint”.

“It's crucial to find equitable solutions with due respect to #HumanRights for all.”

The issue has also caught international attention with celebrities such as pop star Rihanna and environment campaigner Greta Thunberg announcing their support for the farmers. The United States has also urged India to resume talks with farmers.