At least one person was injured today in a bomb blast at a FedEx facility near San Antonio, Texas, authorities told local media.

The explosion of what was apparently a package bomb occurred at 12:30 am at the company's installation in the town of Schertz, according to the sources.

Austin police said that they have a videotape showing the explosion that, the sources said, looked similar to the other four blasts that have occurred in the Texas capital in recent weeks.

The injured person was attended to at a nearby health center and has already been released. At the time of the explosion, there were about 75 employees working at the FedEx installation.

This is the fifth such incident to occur in central Texas so far this month, the latest last Sunday injuring two young men walking along a sidewalk in southwest Austin.

In the other four incidents, two people were killed and four were injured. Given the fact that three of those people were African American and one was Hispanic, authorities suspect that there may be a racial element to the attacks.

Authorities are working with the hypothesis that the same person - a "serial bomber" - is responsible for all the explosions, although they admit that at present they have no suspects.

Nervousness over the recent bombings - and a bomb tip - forced authorities to cancel several events associated with the South by South-West cultural festival in Austin on the weekend. Police arrested one man in the matter and charged him with making a terrorist threat.

Police have recommended that members of the public not open or even touch packages or other objects if they are not certain who sent them.