Tijuana, Mexico  - Tijuana, in the northwestern Mexican state of Baja California and just across the border from the US city of San Diego, is suffering a dramatic escalation of gruesome violence.

Last weekend, police found nine decapitated bodies in one incident and nine other murders perpetrated separately from that.

This is nothing out of the ordinary in the troubled border city of 1.6 million residents, where some 600 people are believed to have been killed so far this year.

And it is also only a fraction of the drug-related killings that have soared to more than 5,000 across Mexico since January, mainly in its northern states. On Thursday alone,
13 bodies were found at one location in San Ignacio, in the Pacific-coast state of Sinaloa, and five people were shot dead in Chihuahua, in the north-central border state of Chihuahua.

But Tijuana has seen some of the worst violence, which has turned the one-time tourist hot spot into a near ghost town.

On November 16, an armed commando burst into the pool room La Banana Loca in Tijuana. They shot their AK-47 rifles indiscriminately. Amid terrorized cries, five people dropped dead among the tables, and seven others were injured.

In October, a commando entered a fish restaurant in the heart of Tijuana. Three men were killed and three others were injured, and the suspects left the scene unhindered and sped away in two vehicles.

Acts of violence have been rising steadily for more than a decade.

Until recently the victims were basically members of two drug gangs - the Gulf Cartel led by Osiel Cardenas and the Tijuana Cartel connected to the powerful Arellano Felix family - which have fought each other for control of the border city.

But increasingly, civilians and bystanders are being killed. In October, a baby was shot dead when it got caught in crossfire. The fate of its parents was not clear, and Mayor Jorge Ramos Hernandez dismissed the situation as deeply regrettable.

Tijuana is one of the most lucrative hubs between the United States and Latin America for drug trafficking, arms smuggling, prostitution and human trafficking.

"The shootings used to take place mostly in the poor neighbourhoods, which were not controlled by the government," says Rodolfo Corona Vasquez, a university researcher and professor at the College of the Northern Border. "Now residents unrelated (to the drug gangs) are increasingly being affected. Life has become unsafe for all of us."

Restaurants and bars in the centre of Tijuana are virtually empty in the wake of attacks.

"People are scared to go out onto the streets after dark," said Adela Navarra, editor of the magazine Revista Zeta.

She knows what she is talking about. The founder of the magazine survived an attack in the early 1990s, but three of its employees have been murdered since Revista Zeta started to report on the machinations of the cartels and the corruption of leading personalities.

On the surface, Tijuana, like other cities in northern Mexico, looks a lot more cheerful and orderly than most cities in central and southern Mexico.

The streets are clean, and people brake at stop signs and red lights and allow pedestrians to cross. Even the heavily-armed military vehicles patrolling the streets respect these rules.

However, the growing insecurity and the fact that the city government is not able to protect its people have had serious consequences for Tijuana's economic development.

The flow of tourists, mainly from the nearby San Diego, who used to flock by the thousand into the bars on Avenida Revolucion for its lively entertainment, has slowed to a trickle.

Investment in factories in the so-called maquiladora industry has dwindled.

Restaurants' sales are down by more than 30 per cent in recent weeks.

"Tourism decreased by up to 50 per cent due to the acts of violence," the head of the Tijuana Tourism Committee, Ana Alicia Meneses, said recently.

Meneses called upon the authorities to fight organized crime with greater determination.

City residents are tired of violence.

The affluent live in permanent fear of being kidnapped or subjected to other forms of extortion. Many have been living with their families across the US border in San Diego, and in recent years, have started moving their businesses to the United States.

The best restaurants in Tijuana have already moved to San Diego or have opened subsidiaries there.

In November, thousands of people marched through city streets to demand drastic changes.

"I am full of frustration - not with crime, not with violence, but with the lack of efficient, competent responses on the part of the authorities," said Erick Rossenberg, a doctor who attended the rally. (dpa)