Cell phones found in the innards of four prisoners at maximum-security prison in El Salvador

(AP) Cellular telephones were found inside four prisoners in El Salvador's maximum-security prison, authorities said Wednesday.

The discovery was made Tuesday at the prison in Zacatecoluca, in central El Salvador, after suspicious officials took X-rays of each of the inmates, federal corrections chief Jaime Villanova said.

The names of the prisoners, all members of the dangerous Mara Salvatrucha gang, were not released in order to avoid jeopardizing an ongoing investigation that began a month ago, he said.

Capt. Juan Ramon Arevalo, director of the prison known as Zacatras, said the gang members had introduced the cell phones, wrapped in plastic bags, into their bodies through their anuses. Authorities also found nine cell phone chips and one charger.

"Each one had a cellular with a number of chips," Arevalo said, adding that one also had hidden a charger in his anal cavity.

The inmates allegedly used cell phones to direct criminal activities on the street from inside the prison, Arevalo said. The smuggled phones were found during an investigation at prisons throughout the country amid complaints from business owners of extortion by gang members.

Prisoners change phone chips frequently to avoid being traced, Arevalo said.

The police have doubled their security levels to combat the criminals.