Brazil's imprisoned former president, Jair Bolsonaro, has undergone a second medical procedure in just three days to treat his persistent hiccups.

Doctors performed a "phrenic nerve block procedure" on Bolsonaro to block his left phrenic nerve, after treating Bolsonaro's right one on Saturday. The phrenic nerve can be found in the neck and is vital in controlling the diaphragm, which controls breathing.

The far-right former leader is currently serving a 27-year sentence after plotting a coup to overturn the 2022 election.

The latest treatments follow a recent surgery for the former president amid ongoing health complications.

Dr Claudio Birolini said that Bolsonaro's "condition is stable" following his second procedure for chronic hiccups on Monday.

Birolini said he did not "believe the hospitalisation will be prolonged much longer".

Bolsonaro was expected to leave hospital on 1 January if his recovery went well, his medical team said.

Bolsonaro, 70, received his first treatment for recurring hiccups on Saturday, which his doctors said "went well".

Days earlier, on Christmas Day, he underwent a successful surgery for a double hernia, his wife Michelle confirmed.

Brazil's Supreme Court allowed the 70-year-old to be transferred from federal police headquarters where he is serving his sentence to a hospital in the capital, Brasília, for the initial surgery.

Bolsonaro had been suffering from recurring hiccups for months, and his medical team deemed it necessary to treat them following his successful surgery.

"It's been nine months of struggle and anguish with daily hiccups," Bolsonaro's wife, Michelle, said on Saturday.

Prior to the hernia surgery, the former president underwent intestinal surgery in April.

Bolsonaro has endorsed his son Flávio to run against Brazil's President Luiz Inácio Lula da Silva in the 2026 presidential election.

Bolsonaro lost the 2022 presidential election to his left-wing opponent Lula.