Florists with wilting bouquets of red roses and street vendors clutching unsold balloons were heartbroken in the Afghan capital on Tuesday after the Taliban's morality police banned Valentine's Day celebrations.

While Valentine's Day has never been widely celebrated in Afghanistan, some well-off residents in cities have developed a tradition of marking the lovers' day in recent years.

In Kabul's famed Flower Street, shops were full of heart-shaped garlands and red stuffed animals, but hopelessly empty of customers.

In the window of one outlet, a poster signed off by the Ministry for the Promotion of Virtue and Prevention of Vice warned shoppers: "Avoid celebrating lovers' day!"

The poster said Valentine's Day "is not Islamic and is not part of the Afghan culture but a sloganeering day of the infidels".

"Celebrating the day of lovers is showing sympathy to the Christian Pope," it read.

Officers from the ministry patrolled the area in their white uniforms, trailed by an armed escort, an AFP correspondent reported.

Kneeling in front of his shop, Omar -- who did not share his surname -- pruned thorns and withered petals from his stock of flowers.

"[The Taliban authorities] published and distributed their order to every shop," he told AFP.

"I don't think I could sell these flowers today, people aren't buying," he said.

"You can see we have no customers -- the situation is very bad."

An AFP reporter saw a young couple furtively buy flowers and quickly leave the scene when they saw the morality police patrol.

"The situation has changed -- we can't celebrate it like other years," said browsing shopper Zahrah, married for seven years.

"But we do celebrate it. There are some restrictions and the situation is not good, but we celebrate it at home."

The vice ministry could not be reached for comment on the exact nature of the ban.

The Taliban authorities have issued various restrictions on social life in the country since they came to power in August 2021.

Music, social media apps and video games have all come under scrutiny by the ultra-conservative government.

The authorities have particularly cracked down on Afghan women, effectively squeezing them out of public life.