NEW DELHI (AFP) - Prime Minister Narendra Modi on Sunday urged a halt to attacks on low-caste Indians, seeking to defuse mounting anger among Dalits over the public flogging of four villagers by cow-protection vigilantes.

Modi described the ongoing exploitation of Dalits, who lie at the bottom of India's deeply entrenched social hierarchal system, as shameful.

"Why should we exploit our Dalit brothers? What right do we have for such behaviour?" Modi said to workers of his Hindu nationalist party in the southern city of Hyderabad.

"It is our responsibility to protect and respect the persons from society's lowest rung." Modi has faced criticism for remaining silent over the attack on the villagers last month by so-called cow-defenders in his home state of Gujarat.

Footage showed four half-naked men tied to a car as the activists took turns to thrash them with belts and batons at a crowded marketplace.

Video of the beating of the four Dalits - who were taking a dead cow to be skinned - went viral on social media. Violent protests erupted over the attack late last month, leaving one police officer dead.

Dalit activists have said the unrest reflects deep frustration after years of discrimination by those from higher castes.

Experts say their anger could harm Modi's party's chances at elections next year in three key states, where Dalits make up a sizeable chunk of voters.

"Don't attack any Dalits. Shoot me if you have to, but not the Dalits," Modi said late Sunday.

"Attack me, but not them. Don't harm them. This game must end." The comments come the day after the premier also broke his silence on the self-styled cow defenders, saying any vigilantes should be prosecuted.

Modi repeated his comments on Sunday, telling a rally they were simply trying to divide India.

"I want to ask the state governments to identify such men and take strict action against them," he said.

Cows are considered sacred by Hindus and killing them is banned in most Indian states.

Formerly known as "untouchables", Dalits are commonly tasked with removing the corpses of dead cows from streets, where the animals often roam freely.

Attacks by vigilante groups on cow traders and smugglers have increased since Hindu nationalist Modi won power in 2014.

At least five Muslim men were killed last year by Hindu mobs on suspicion of eating beef or smuggling cows across the country.