Religious activists in India and Pakistan have begun separate protests against Valentine's Day celebrations, saying they are an insult to Hinduism and Islam.
In Bombay, members of the right-wing Shiv Sena group raided shops and burned Valentine's Day cards.
Police nationwide boosted security to head off the violent protests that have occurred in recent years.
In Pakistan, fundamentalist students condemned Valentine's Day as a day of shame and lust.
Bombay protest
Both sets of activists regard the festivities as running counter to the cultural ethos of their societies.
Shiv Sena - part of India's ruling coalition government - has been behind repeated attempts to ban celebrations.
"[Valentine's Day] is nothing but a Western onslaught on India's culture to attract youth for commercial purposes," said senior Shiv Sena leader Uddhav Thackeray, son of group leader Bal Thackeray.
Last week, Bal Thackeray said anyone wanting to avoid violence on Valentine's Day should not celebrate it.
On Tuesday, 20 Shiv Sena activists stole cards from a shop in central Bombay.
Shouting "long live Shiv Sena", they burned the cards on the pavement outside.
Bombay police would be on full alert to ensure Friday passed peacefully, a senior police official, Himanshu Roy, told the BBC.
Other Hindu fundamentalist parties like the Vishwa Hindu Parishad and Bajrang Dal have also said they will oppose Valentine's Day celebrations.
Hotel balls
In Pakistan, the student wing of the fundamentalist Islamic party Jamaat-e-Islami also called for a ban on Valentine's Day celebrations.
Khalid Waqas Chamkani, a leader of the wing in North-West Frontier Province, said: "This is a shameful day. The people in the West are just fulfilling and satisfying their sex thirst."
He condemned "moderate elements" for allowing Western festivities.
"They are following the West just to show that they are modern people," Mr Chamkani said in the provincial capital, Peshawar.
However, celebrating Valentine's Day, named after the Christian patron saint of lovers, has become increasingly popular in both India and Pakistan.
Many hotels in both nations put on Valentine's dinners and balls, while the media allow lovers radio and newspaper slots to broadcast messages.
One card stockist in Bombay said couples would celebrate the day despite the protests.
"It is just sad for poor shop owners who are the unlucky targets," he said.
Lucknow student Latika Arora went further.
"No one has the right to work as the morals police," she said.
"We should be able to celebrate Valentine's Day as we wish."