MADRID (AP) — Police in Spain discovered a bomb-making workshop in the home of a 74-year-old man charged with terrorism for sending six letters containing explosives to high-profile diplomatic and government targets, the Spanish Interior Ministry said Friday.

Spain’s National Court said earlier it had charged the retiree with six offenses for allegedly sending letter bombs to the country's prime minister and to the U.S. and Ukrainian embassies in Madrid. An employee at the Ukrainian Embassy was slightly injured while handling one of the letters.

An Interior Ministry statement issued as the suspect appeared in court Friday detailed items in the man's home that indicated meticulous planning had gone into making the letter bombs.

“Inside the house, the investigators found a workshop with tools, welding, metal elements and screws,” the statement said. Preparations were underway “aimed at the manufacture of new devices,” according to the ministry.

The as-yet-unidentified man appeared before a judge in Madrid and was detained without bail, the National Court said. The suspect, referred to only by the initials PGP in court documents, was arrested in the northern city of Miranda de Ebro on Wednesday.

He was charged with the manufacture and use of explosive devices for terrorist purposes, according to court documents. Two of the alleged offenses were classified as aggravated since they involved targeting members of the government.

Spanish media reported that the suspect had links to Russia, was strongly active on social media and was regarded by authorities as a flight risk.

The six letter bombs were sent in November and December and required the intervention of bomb-disposal experts. One was destroyed after being dispatched by regular mail to Spanish Prime Minister Pedro Sánchez.

Letters with similar characteristics were sent to Spain’s Defense Ministry, a European Union satellite center located at the Torrejón de Ardoz air base outside Madrid and an arms factory in northeastern Spain that makes grenades sent to Ukraine.

An envelope intercepted at the U.S. Embassy’s security screening point in December was destroyed by a bomb squad after a wide area in the center of Spain's capital was cordoned off.

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