Mexico's popular songs glorifying its drug traffickers, known as narcocorridos, have attracted a growing following in recent years, from Mexico City to Los Angeles.

But authorities in northwestern Sinaloa for the first time banned the ballads in May, surprising many in the home state of Mexico's oldest drug cartel, the Sinaloa cartel, where drug trafficking and its often ostentatious culture are omnipresent.

The ballads are part of a decades-old drug culture, but the new wave of narcocorrido is more gruesome than ever with tales of the life and loves of drug traffickers and accounts of bloody clashes with security forces.

Sinaloa, which lies on the Pacific coast, is one of the three most violent states in the country, recording 2,505 murders last year, according to national statistics.

Killings in parts of Mexico have shot up in recent years amid a military crackdown on organized crime which has sent soldiers onto the streets.

Sinaloa authorities issued the ban on narcocorridos in places selling alcohol to avoid "excuses for crime" and to try to reduce the murder rate, according to state government head Gerardo Vargas Landeros.

Narcocorridos gained popularity in the 1970s and 1980s, with their tales of danger and the exciting lives of drug barons, such as Felix Gallardo, who is now in jail.

But the newer songs have taken a darker turn, in what is nicknamed Movimiento Alterado or Altered Movement, with songs focusing on weapons and the ever more gruesome ways in which scores are being settled.

"They had very sophisticated weapons in their possession. They had .50 caliber (weapons) and they used grenades bazookas and AK-47s.

They came in armored cars ... They put up a roadblock ... and all hell broke loose. They fought for almost an hour ... the men died under a hail of bullets," recounts one ballad.

That song, the tale of a clash between soldiers and hitmen for "El Chapo" -- the billionaire fugitive head of the Sinaloa cartel -- is one of the most popular, said Aldo Alberto Garcia, a member of a band called "The Sinaloa Three."

The Altered Movement got its start distributing songs on the Internet shortly after President Felipe Calderon ordered 50,000 troops into battle against organized crime gangs at the end of 2006.

Since then, beheadings, mutilations and shootouts have increased as the gangs fight each other and security forces in a bloodletting that has claimed 41,000 lives, according to media counts.

The songs reflect the shifting realities.

"We've started to see a change in narcocorrido toward hyper-violence," said Juan Carlos Ramirez-Pimienta, an academic from the University of San Diego, California, who recently published a book on the ballads.

"The production of narcocorridos is immense, it's impossible to work out how many bands exist," he added.

And despite the ban in Sinaloa, which follows similar moves in the country's most violent state of Chihuahua and the border city of Tijuana, the music plays on.

The Sinaloa government has so far closed 36 establishments out of 5,400 in the state for playing narcocorridos, according to official figures.

"I don't play them any more on my program," said radio presenter Jorge Ramos, whose company toes the government line and sees the songs as a small part of the overall market.

But narcocorridos ring out from other radio stations on the streets and in music videos in bars and restaurants throughout the mountainous state.

Bands still plays in seedy bars near the market in Culiacan, the state capital, where stalls sell narcocorrido CDs as well as bright T-shirts bearing images of weapons and jewel-incrusted gun handles.

Performers in cowboy hats gather every night on a central street of Culiacan where they hope to be hired to play a song.

They may be paid by drug lords to write about their exploits and some are known to perform for drug gangs.

"Whether narcocorridos exist or not, the violence won't stop. As long as there's drug trafficking this music will continue," said one singer, a guitar slung over his back.