India has witnessed a spate of lynchings by Hindu extremist "cow vigilantes" targeting Muslims and low-caste Dalits accused of killing cows or eating beef and other mob attacks over child kidnapping rumours.

Akbar Khan, 28, was walking with another person and two cows through Alwar district, around 100 miles (160 kilometres) from the state capital Jaipur, when some local villagers attacked them late Friday night.

"The incident of alleged lynching of a person transporting bovines in Alwar district is condemnable," Rajasthan's chief minister Vasundhara Raje tweeted after the incident. 

"Police have registered a case and are questioning two suspects. Strictest possible action shall be taken against the perpetrators," she added.

The police suspect Khan was killed on suspicion of cattle smuggling but said it was too soon to say anything conclusively.

"Two main suspects are known anti-social elements and we are questioning them for more details on the incident," Shyam Singh, assistant superintendent of Alwar police, told AFP.

"The cows are with the police and the victim's body has been sent for post-mortem," he added.  

Singh said police did not yet know how many attackers were involved and were questioning locals close to site of the incident.

The latest attack comes days after India's top court asked the government to enact a new law to stem "horrendous acts" of lynchings across the country.

At least 22 people have been killed by mobs in different parts of India over issues ranging from cattle theft, eating beef and rumours of child kidnapping this year. 

Cows are considered sacred in Hindu-majority India, where squads of vigilantes roam highways inspecting livestock trucks.

Slaughtering cows is illegal in many Indian states and some also require a licence for transporting them across state borders.

Another Muslim man was killed in Alwar last April when vigilantes attacked his cattle truck passing on the highway.

Critics say the vigilantes have been emboldened by the election in 2014 of Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party.

Modi had earlier criticised the cow-protection vigilantes and urged a crackdown against groups using religion as a cover for committing crimes.