Brazilian President Jair Bolsonaro will undergo tests for an obstructed intestine after being admitted to hospital with persistent hiccups.

He could require emergency surgery, his government's office said today, in his latest health complication from a 2018 stabbing.

Mr Bolsonaro, 66, went to the military hospital in Brasilia early this morning, with the president's office initially saying it was to undergo tests for chronic hiccups.

Later, a spokesperson said the surgeon who operated on the president in 2018 had decided he should go to Sao Paulo for additional tests to investigate the obstructed intestine.

Medic Antônio Luiz Macedo said Mr Bolsonaro may possibly need emergency surgery.

The Brazilian far-right leader nearly died after being stabbed in the gut on the campaign trail in 2018, resulting in multiple follow-up surgeries.

On Twitter after the news of his transfer to Sao Paulo, Mr Bolsonaro said he was confronting "one more challenge" and thanked people for their prayers

Mr Bolsonaro's son Flavio said his father had been having trouble talking.

Speaking on CNN Brazil, the federal senator said that if his father needs to undergo surgery, it should not be a serious procedure.

He added that doctors had removed liquid from the president's stomach.

Speaking to a local radio station last week, Mr Bolsonaro had said: "This happened to me before, maybe due to the medicine I'm taking, I have hiccups 24 hours a day."

The tired-looking leader last night complained to supporters outside his official residence in Brasilia about the problem.

"People, my voice has gone. If I start talking a lot, the hiccups return ... they already have," he said.

After being stabbed on the campaign trail in September 2018, President Bolsonaro has undergone several surgical procedures on his abdomen since he was elected.

He also contracted Covid-19 last year, although his symptoms were mild and he did not need hospital treatment.