US Secretary of State John Kerry will fly home for treatment after breaking his leg in a cycling accident in the French Alps, putting America’s chief diplomat temporarily out of commission.

Mr Kerry, 71, a keen cyclist, was hospitalised in the Swiss city of Geneva – where he was meeting his Iranian opposite number Mohammad Javad Zarif – after the accident across the border in the French Alps.

But White House spokeswoman Jennifer Psaki, who used to work for Mr Kerry at the State department, claimed the accident would not slow down the globetrotting envoy.

• Kerry in hospital after cycling accident

“I would love to see anyone at the hospital try to stop John Kerry from negotiating and working while recovering from breaking his leg,” she tweeted.

Mr Kerry was initially expected to return to the United States on Sunday evening, but the State Department later announced the flight had been postponed.

“The Secretary had planned on flying back to the US this evening, but after further consultation it was sensible for him to remain in the hospital for observation overnight for purely precautionary measures and fly home tomorrow,” spokesman John Kirby said.

He added that Mr Kerry was “in great spirits and active”, and had spoken by phone with President Barack Obama.

Mr Kerry’s fall happened after he had just set out on a planned ride of one of the stages of the Tour de France, the challenging Col de la Colombiere mountain pass, a local source said.

The top US diplomat, who had been holding talks in Switzerland on Saturday on the Iran nuclear crisis, broke his right femur in his fall in the village of Scionzier near Chamonix.

He has had to cancel both a trip to Spain and his attendance at an international meeting in Paris on the crisis over the Islamic State group, Mr Kirby said.

He added however that Mr Kerry planned to “remotely” join Tuesday’s Paris talks, which are aimed at reviewing the international coalition’s strategy against the jihadists, who have seized swathes of territory in Iraq and Syria.

The State Department said Deputy Secretary of State Antony Blinken will lead the US delegation at the Paris talks instead.

“The secretary is stable and never lost consciousness, his injury is not life-threatening, and he is expected to make a full recovery,” Mr Kirby said in a statement earlier on Sunday.

“Given the injury is near the site of his prior hip surgery, he will return to Boston … to seek treatment at Massachusetts General Hospital with his doctor who did the prior surgery.”

A senior State Department official told CNN on Sunday that US surgeon Dennis Burke, who performed a past hip surgery on Mr Kerry, was heading to Switzerland and would accompany him back to America.

– AAP, with Nina Larson in Scionzier