A Hindu group's ban on Valentine's Day was largely shrugged off, however, by thousands of young lovers in Indian cities.
In this tradition-steeped country where public displays of affection, including hand-holding, is often taboo, Valentine's Day was little-known until some years ago.
Now newspapers carry Valentine's Day messages, ads for stuffed hearts and cards, and interviews with celebrities about their thoughts on love. Restaurants offer Valentine's Day specials to lure young couples.
A few slogan-shouting men, believed to be members of the Shiv Sena party, walked into the busy Wimpy's fast food restaurant in New Delhi's central Connaught Place, where they smashed potted plants, tossed a few chairs and knocked over people's trays. Terrified customers streamed out of the restaurant, which soon closed its shutters.
Half a dozen police soon arrived with wooden truncheons. The attackers dispersed and no arrests were made.
Witnesses said they shouted, ``Long live Shiv Sena!''
The Shiv Sena party opposes the growing influence of Western culture on Indian society and has launched a bitter campaign against Christians and Muslims, whom it considers foreign in India, a largely Hindu but officially secular nation.
That stand has been criticized even by the powerful World Hindu Council, which champions conservative causes.
``We are against violence on this issue. We should create awareness among the youth and tell them that the concept of Valentine's Day is alien to Indian culture,'' said Giriraj Kishore, senior vice president of the council.
In many Indian cities, police kept watch as thousands of young lovers trooped into shopping arcades and restaurants decorated with red balloons, flowers and festoons. Music played. Chocolates and roses were swiftly sold.
``Valentine's Day has caught on in India. It's the young people who have chosen to adopt it. The Shiv Sena is just creating a nuisance,'' said Aman Deep, owner of a card and gift shop.
In Connaught Place, young customers packed outlets of McDonald's, Pizza Hut and the homegrown fast food chain, Nirula's, where big discounts were offered.
``Do I look like I care about Shiv Sena?'' asked Hemant Patodia, holding a red rose in one hand, as he cuddled his shy girlfriend with the other.
Mobs in New Delhi torched effigies of St Valentine late Tuesday, while Shiv Sena supporters also raided card shops and destroyed Valentine decorations in a series of orchestrated attacks, police said.
The Madness disco in the Khar district of the city was also attacked, and ink was sprayed on shop windows.
Trouble also flared late Tuesday in the northern city of Lucknow in Uttar Pradesh state.
Press reports said police stood by in Lucknow as gangs from the radical Hindu Jangran Manch group fought running battles with card vendors.
The authorities on Wednesday closed down Lucknow University, saying Valentine's Day would trigger lewd behaviour, the rediff.com website reported.
"Eve-teasing has been on the rise in and around the campus and a day like Valentine's will give undesirable elements a chance to take undue liberty," said university vice chancellor D.P. Singh.
Police and paramilitary soldiers were deployed at shopping malls across Uttar Pradesh on Wednesday to prevent arson attacks, officials said.
But State Chief Minister Rajnath Singh said he was not concerned about the threats of violence.
"The protests on Valentine's Day celebration is not at all an issue for us. If some Hindu organisations are trying to create cultural awareness among today's youth, it is their business," he said.
As Hindu nationalist political parties have gained more political power, radical groups have taken to disrupting any event deemed to conflict with traditional Hindu culture, ranging from films containing too much sex to beauty pageants and cricket matches against Pakistan.