The Vatican has hit out at what it calls an "anti-clerical, leftwing" campaign against Pope Francis, strongly rejecting accusations concerning his actions during Argentina's brutal military dictatorship.

In a statement at a press briefing on Friday, Federico Lombardi, the pope's spokesman, said the allegations against Jorge Bergoglio, who until Wednesday was the archbishop of Buenos Aires, "must be clearly and firmly denied". "There has never been a concrete or credible accusation in his regard. Argentinian justice interrogated him once … but he was never charged with anything," he said. "He documented his denials of the accusations against him. There are also many declarations that show how Bergoglio tried to protect many people in his time during the military dictatorship. His role is very clearly noted."

The Roman Catholic church has been widely criticised for failing to stand up to the junta that ruled Argentina between 1976 and 1983. Some critics have gone further in their attacks on Bergoglio, claiming he failed to protect two Jesuit priests serving under him who were abducted and tortured for five months at a navy base.