The ban is being called the "strike of crossed legs"

Dozens of women are said to be taking part in what is being called the "strike of crossed legs", a move backed by the mayor of Pereira.

The city in Colombia's coffee-growing region reported 480 killings last year.

A city official said the idea came from a meeting of wives and girlfriends over the progress of a disarmament scheme.

Rap song

"We met with the wives and girlfriends of gang members and they were worried some were not handing over their guns and that is where they came up with the idea of a vigil or a sex strike," the mayor's spokesman told Reuters news agency.

"The message they are giving them is disarm," he added.

Studies found that local gang members were drawn to criminality by the desire for status, power, and sexual attractiveness, not economic necessity, Colombian radio reported.

One of the girlfriends, Jennifer Bayer, told Britain's Guardian newspaper: "We want them to know that violence is not sexy."

Ms Bayer said the women had come up with a strike anthem rap song that included the lyrics: "As women we are worth a lot. We don't want to fall for violent men because with them we lose too much."