There were "hundreds" of bikers from as many as five different gangs present when the firefight broke out midday Sunday, according to police sergeant W. Patrick Swanton.

"I was amazed that we didn't have innocent civilians killed or injured," Swanton said.

The bikers also used baseball bats and knives during the showdown, which started with a fistfight inside "Twin Peaks" sports bar and continued at the parking lot.

"There is blood everywhere. We will probably approach the number of 100 weapons," Swanton told the Waco-Tribune Herald newspaper.

Restaurant warned

Police were present at the scene before the violence started, and some of the armed bikers were shot by the security forces, according to Swanton.

The authorities of the central Texas town warned the chain restaurant of possible danger.

"Apparently the management (of Twin Peaks) wanted them here and so we didn't have any say-so on whether they could be here or not," Swanton said.

Swanton did not identify the gangs involved in the skirmish. However, many men wearing vests inscribed with the words "Bandidos" or "Cossacks" were seen in Waco, which has a population of about 129,000 people.

Fear of retaliation

Officials were stepping up security in the area to prevent further violence late Sunday.

"We are closing the entire Central Texas Marketplace if you are here leave now. For safety reasons we again assert do not come to this area!" Waco police said on Facebook.

"Officers are continuing to arrest individuals coming to the scene with weapons. This is not the time to sight see as we are dealing with very dangerous individuals," they said.

Three armed bikers were arrested while trying to enter the scene of the shooting and retaliate against their rivals.

Although causes of the violence were not immediately clear, officials say that tensions between different criminal fractions were simmering for months. The gangs are known to have disputed over turf and recruitment efforts in the past.

dj/rc (AP, Reuters, dpa, AFP)