Authorities found a well-stocked arsenal at a prison in the central state of Falcon that was evacuated last week for renovations, the minister responsible for Venezuela's penitentiary system said Monday.

Hidden inside a tunnel dug by inmates, the arms cache included machine guns, grenades, C4 plastic explosives and more than 11,000 rounds of ammunition, Iris Varela told a televised press conference.

The weapons and ordnance, some of it military issue, were carefully packed to prevent damage from the high humidity underground, she said.

The arsenal was discovered after the roughly 1,000 inmates at the prison in Coro, the state capital, were removed last Friday as part of an initiative to renovate Venezuela's vastly overcrowded penitentiaries.

Two inmates died and 13 were injured when some elements in the prison population resisted the removal.

Varela blamed the violence on a "minority of negative leaders" who control trafficking in arms, drugs and other contraband inside the prison and were unwilling "to lose the business they have there."

Found along with the arms cache were receipts for bank deposits and both the account-holders and the depositors are being investigated, the minister said.

She acknowledged the involvement of some "civilian and military" officials in supplying guns and drugs to inmates.

The government embarked last week on an emergency program to renovate Venezuela's 30-odd existing prisons and to build 20 more.

Violence in Venezuelan penitentiaries claimed 304 lives in the first half of the year, an increase of 15 percent over the same period in 2011.

The system is also holding more than 45,000 people, three times its official capacity. EFE