Four prisoners in an El Salvador jail hid mobile phones, a phone charger and spare chips in their rectums so they could co-ordinate crimes from their cells, authorities said Wednesday. The surprising discovery was made Tuesday after some officials got suspicious of the activities of the inmates and an X-ray thereafter revealed the situation, federal corrections chief Jaime Villanova told the AP.

The men, all members of the dangerous Mara Salvatrucha gang, wrapped their phones and accessories in plastic and inserted them into their rectums, Capt. Juan Ramon Arevalo, director of the Zacatecoluca prison known as Zacatras told the AP, adding that the phones were relatively small, about as long as an adult forefinger.

Authorities also found nine cell phone chips, each slightly larger than a fingernail, and one charger.

The inmates allegedly used the mobile phones to manage the criminal activities outside, Arevalo said.

The smuggled phones were found during an investigation that began a month ago at prisons throughout the country following complaints from business owners of extortion by gang members.

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