By Tibisay Romero

VALENCIA, Venezuela, March 28 (Reuters) - Dozens of people were feared dead after rioting and a fire in the cells of a Venezuelan police station, an official and witnesses said on Wednesday, although authorities did not say how many were killed.

State official Jesus Santander said the state of Carabobo was in mourning after the incident in the city of Valencia.

"Forensic doctors are determining the number of fatalities," Santander said. A policeman was shot in the leg and was in stable condition and firefighters had extinguished the flames, he said.

Venezuelan media said there could be more than 60 fatalities.

Prisons in Venezuela are notoriously overcrowded and filled with weapons and drugs.

"There are people who are inside those dungeons ... and the authorities do not know they exist because they do not dare to enter," said Humberto Prado, a prisons rights activist. (Aditional reporting by Vivian Sequera Writing by Girish Gupta and Vivian Sequera Editing by Paul Tait)