Ten people were injured Thursday in a brief distubance at a prison in the western Puerto Rican city of Mayaguez, police said.

The district police commander, Jorge Velazquez, said that around 12:30 p.m. about 500 inmates took over one of the cellblocks and tried to cross to another one.

"The incident required the use of tear gas inside to pacify the situation," a spokesman for the Puerto Rican Department of Correction and Rehabilitation told Efe, insisting however that the figure of 500 prisoners was exaggerated.

Velazquez told Efe that six prisoners and four guards were injured in the incident.

He said two of the six prisoners who were hurt suffered serious injuries and that one of them is in critical condition, while the guards were injured only slightly.

Meanwhile, DCR chief Carlos Molina Rodriguez said in a communique that the situation is under control.

He said that the incident started with a fight among several prisoners when they were being escorted to their cells, two of whom needed to be taken to the Medical Center in Mayaguez.

"The officers who intervened in the dispute ended up with slight injuries in the altercation. The situation at this time is under control and the attackers have been identified, will be isolated and eventually prosecuted with all the rigor of the law," said Molina.