Why did a Rihanna tweet prompt Indian backlash?

Hours after a tweet by pop superstar Rihanna drew global attention to the cause of protesting farmers, India launched an unprecedented backlash against the Barbadian singer.

The ministry of external affairs released a formal statement criticising "celebrities and others" for their "neither accurate nor responsible" comments, and top ministers and celebrities tweeted against "propaganda" that threatened India's unity, reports BBC.

Some pro-government news channels amplified the establishment voice; one Bollywood actress known for her pro-government opinions called Rihanna a "porn star"; and misogynistic trolls even hailed her ex-boyfriend Chris Brown for assaulting her in 2009.

Rihanna's tweet on Tuesday linked to a news story about the internet blockade at the protest sites and soon went viral, gaining more than 700,000 likes. "Why aren't we talking about this?!" wrote the singer, who has 100 million followers on the social network.

The government pushback was swift, led by Home Minister Amit Shah who tweeted on Wednesday night with hashtags #IndiaAgainstPropaganda and #IndiaTogether. "No propaganda can deter India's unity! No propaganda can stop India to attain new heights! Propaganda can not decide India's fate… only 'Progress' can. India stands united and together to achieve progress," he wrote.

Soon afterwards, ministers, Bollywood stars and cricketers also began tweeting, using one or both of the hashtags used by Mr Shah.

"India's sovereignty cannot be compromised. External forces can be spectators but not participants. Indians know India and should decide for India. Let's remain united as a nation," wrote cricketer Sachin Tendulkar.

Similar or even identical tweets were shared by several celebrities, including Indian captain Virat Kohli, Bollywood's Akshay Kumar, Ajay Devgn and Karan Johar, legendary singer Lata Mangeshkar and tennis player Saina Nehwal - leading to suggestions that the messages were co-ordinated by social media managers from the governing Bharatiya Janata Party (BJP).

The protests have become the most intractable challenge for Prime Minister Narendra Modi's government.

Tens of thousands of farmers have been protesting at Delhi's borders against three new farm laws for more than two months.

The protesters, including elderly men, women and children, have refused to budge even during the freezing winter temperatures, camping in the open, living and sleeping on the streets. Dozens have died too.

The government has offered to suspend the laws for 18 months, but the farmers say they must be repealed.

Last week, the protest hit global headlines when a tractor rally by farmers ended in violent clashes, which left a protester dead and hundreds of policemen and protesters injured. Some demonstrators stormed Delhi's historic Red Fort and occupied it until police chased them away.

As Rihanna's tweet went viral, gathering tens of thousands of responses, many hailed her for bringing global attention to "an important cause". But many also criticised her for wading into the protests against the laws that have been defended by the government and its supporters.