SAN SALVADOR, El Salvador — A Salvadoran woman was detained after she tried to smuggle a military grenade and marijuana hidden in her vagina into the country’s main prison, authorities said Wednesday.

Officials subsequently raised the security level at jails across the country, prison system spokesman Alberto Uribe said, adding the discovery showed “the inmates are planning something.”

Lidia Alvarado, 44, was found hiding a cylinder containing the weapon and the drugs, as she entered La Esperanza prison on the northeastern outskirts of the capital of San Salvador, Uribe said.

She was turned over to police and charged with illegal weapons possession and drug trafficking, he said. Police who inspected the M-67 grenade said it was in working condition.

Alvarado was visiting two inmates, serving 25 and 30 years. Each had been convicted of rape, robbery and illegal arms possession.

Prison Director Wilson Galeas was quoted by the daily newspaper La Prensa Grafica as saying it was not the first time Alvarado had visited the two convicts.