Feb. 15 (Bloomberg) -- Two bombs exploded this afternoon near police headquarters in the heart of Mexico City, killing one person and injuring at least one more.

The blast occurred near the intersections of Florencia and Chapultepec streets in the city's Zona Rosa neighborhood, a district popular with tourists south of the main business area.

There were no immediate claims of responsibility.

The bombs may be the work of drug traffickers or a small rebel group known as the EPR, said Jorge Chabat, a political science professor at the Center for Economic Research and Teaching in Mexico City. More than 2,000 people were killed last year in drug-related violence, and there have recently been high profile arrests in the capital. The EPR bombed oil pipelines last year as part of an anti-government campaign.

Joel Ortega, head of Mexico City's security secretariat, said the man killed in the blast may have been carrying an explosive device when it detonated. A 30-year-old woman who was injured and taken to a hospital with burns asked questions about the dead man, suggesting they may have been a couple, he said in an interview on CNN en Espanol.

Ortega said that one of the bombs was homemade and probably detonated by a mobile phone, El Universal newspaper reported on its Web site.

Arturo Escanilla was working at a restaurant on the same block and said it sounded like a lightning strike. He felt his building shake.

`Afraid'

``All the windows broke, I was a little afraid,'' he said.

Several cars at the scene appeared damaged by the blast, and more than 100 police were in the area controlling traffic and keeping bystanders away. Bomb technicians were also on the scene, and they used a robot to open and search a parked car.

The explosions occurred about 200 meters (650 feet) away from the city's police headquarters. They were audible from blocks away.

A rebel group called the Popular Revolutionary Army, or EPR, bombed Petroleos Mexicanos pipelines in July and September. No one was injured. The group released a statement last month saying they would warn the government about future attacks.

The group has said it's seeking the release of two of its members held by the government. Federal officials say they aren't holding the men and deny having arrested them.

The EPR was founded in 1996 in the southern states of Oaxaca and Guerrero, two years after the Zapatista Army for National Liberation had an uprising in the state of Chiapas.

Narco Crackdown

President Felipe Calderon has sent thousands of troops to patrol northern border cities where drug violence has escalated. In the last month, federal police have arrested dozens of people they say are members of the Sinaloa drug cartel in Mexico City. They have also found arsenals of automatic weapons, grenade launchers and bullet-proof vests.

Calderon's effort to take on drug traffickers has led to reprisals against government officials in the past, said Gerardo Munck, associate professor of International Relations at the University of Southern California.

``It's a huge challenge to the state. If you're going to have a democratic system, you can't have this level of violence,'' Munck said in a telephone interview.

If the bombing turns out to have been an amateur explosive that went off prematurely, the threat is less significant, Munck said.

Mexican police evacuated the city's tallest building in August after receiving a bomb threat, and later found a small explosive device in a car parked in the building's garage. There was no claim of responsibility.

To contact the reporter on this story: Andres R. Martinez in Mexico City at amartinez28@bloomberg.net; William Freebairn in Mexico City wfreebairn@bloomberg.net.

Last Updated: February 15, 2008 20:00 EST