The row came to a head after members of the Latin Kings gang, which has been registered as a cultural association by the regional government of Catalonia, travelled to Madrid - where state prosecutors are trying to have them labelled as an organised crime gang - to meet the local youth ombudsman.

Madrid's regional government distanced itself from the meeting with the official. "We will never legalise groups like the Latin Kings, who have broken the law and are considered by the legal system to be part of organised crime," a spokesman said.

While members of gangs like the Latin Kings and the Ñetas make headlines for gang fights and murders and rapes in and around Madrid, their counterparts in the eastern region of Catalonia are being encouraged to hold meetings, play football and organise hip-hop concerts.

With their secret rites of passage, strange codes, titles like king and queen and their insistence that their members around the world form a "nation", the Latin American gangs are an alien phenomenon for Spain.

News of fights and murders has made Spaniards nervous of the baggy-trousered, baseball cap-wearing boys and the heavily made-up girls who hang out together in parks and squares.

"Groups like the Latin Kings and the Ñetas are thugs and delinquents," two Spanish journalists, Santiago Botello and Angel Moya, wrote in a book about them.

A variety of groups use the same names, explaining why Latin Kings in Madrid are involved in court cases accused of murders, kidnappings and rapes, while Latin Kings in Catalonia claim to have no contact with crime.

"There are few groups of criminals, but that does not mean that all the young people who adopt a certain form of dress or musical taste should be criminalised," said Erika Jaramillo, alias Queen Melody, an Ecuadorian immigrant.

"The Latin Kings are not a crime group," an anthropologist, Carles Feixa, who has helped the Socialist-run Catalan government to legalise the group, told El País. "It is an organisation for help and solidarity among young Latin American immigrants."

Authorities in the Catalan capital of Barcelona believe that fewer than half the 600 people in the city who consider themselves to be Latin Kings - including some in jail - have signed up to join the newly legal group. The groups, who have their origins in such countries as Ecuador and Peru, have described themselves as a "Latino" self-defence force, willing to use violence to defend their own people.

Their critics allege that male gang members claim "ownership" of female members. "Once you become a Latin Queen the only way out is death," one former member was told. The Latin Kings have allegedly been involved in four murders in Madrid, while only one has been registered in Barcelona.

Barcelona is now trying to follow a US initiative, brokering "peace" agreements between rival gangs.

Backstory

The Latin Kings were founded by Puerto Ricans in Chicago in the 1940s. By the 1970s they had spread across the US and were involved in organised crime, especially drug trafficking. The organisation has also spread through Mexico and Latin America. The Ñetas were created in a Puerto Rican prison in the 1970s. They spread to the east coast of the US in the 1980s, where they were once led by a woman known as La Madrina. Mara Salvatrucha started in Los Angeles among immigrants fleeing the war in El Salvador in the 1980s. Members have tattoos in Gothic lettering. "MS" and "13" are the most popular tattoos.