New secretary of state for the Vatican

Pope Francis has named a veteran Vatican diplomat as the new secretary of state, in what is seen as his most significant appointment since he became leader of the Catholic Church in March.

Archbishop Pietro Parolin's appointment on Saturday ends the era of Tarcisio Bertone, 79, who was widely blamed for failing to prevent ethical and financial scandals that marked the eight-year reign of former Pope Benedict, who resigned in February.

"The Holy Father has accepted... the resignation of His Eminence Cardinal Tarcisio Bertone," the Vatican said in a widely-expected announcement, adding that the changeover would formally take place on October 15.

Parolin, a 58-year-old Italian cleric, is currently the Vatican's nuncio - or ambassador - in Venezuela and has worked on improving ties with China.

Parolin is the youngest cleric to occupy the Vatican "prime minister" post since Eugenio Pacelli, another diplomat who was appointed secretary of state in 1930 at the age of 53 and went on to become Pius XII.

"I feel the full weight of the responsibility placed upon me: this call entrusts to me a difficult and challenging mission," Parolin said in a statement.

Parolin will act as the pope's prime minister and chief aide.

Although he has no power to rule on doctrinal issues, the secretary of state sits in when the pope is ill.

He sets the tone for the Vatican's central administration, known as the Curia, and is involved in everything from finances and the appointment of bishops to diplomatic relations with more than 170 countries.

Bertone, who was secretary of state for nearly all of Benedict's pontificate, was accused of not keeping a close enough watch on the Curia, some of whose members have been accused of corruption and cronyism.

One of the most damaging scandals to hit the Vatican under Bertone was "Vatileaks", when Benedict's butler stole documents alleging corruption from the pope's desk and leaked them to the media.

Parolin was the Vatican's deputy foreign minister for seven years until 2009, has also served in Nigeria and Mexico and diplomatic relations with Israel.