Posing as a public official, he also called nursing homes, football clubs and even the press to spread false information about coronavirus.
Spanish police have arrested a COVID-19 denier for inciting violence and hatred on social media.
The 38-year-old used fake social media accounts to claim health professionals and the media were behind a "COVID farce" and urged his followers to attack politicians, police said on Friday.
"All this would be solved with a shot to the back of (Spanish Prime Minister) Pedro Sanchez's head," he wrote on his accounts.
Police said he also posed as a public official in telephone calls to nursing homes, hospitals, football clubs and the media to spread false data about the pandemic in Spain.
His misinformation activity caused "serious dangers" to public health, Spanish authorities said.
He also allegedly threatened to burn down a local newspaper office and spread slander about the Military Emergencies Unit, a branch of Spain's armed forces.
Police managed to track him down after they found he "was connected to foreign servers, and using SIM cards from other countries, which he changed frequently".
The man was finally arrested after a police search that lasted weeks in Cuarte de Huerva, just outside the northeastern city Zaragoza.
He faces charges of "usurpation of public functions", "threats", incitement to hatred", and "slander against authorities and public officials".
Spain is one of Europe's hardest-hit countries by the pandemic with almost 440,000 COVID-19 cases and over 29,000 deaths.