In this picture taken on March 16, 2015 US Secretary of State John Kerry rides his bike during a break in Lausanne. (Agence France-Presse)
US Secretary of State John Kerry will remain in hospital in Geneva overnight after breaking his leg in a cycling accident in the French Alps and will fly home for treatment on Monday, cutting short a European trip.
Kerry, 71, a keen cyclist, was hospitalised in the Swiss city of Geneva after the accident across the border in the French Alps.
He 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 Kerry was "in great spirits and active" and had spoken by phone with President Barack Obama.
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 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, Kirby said.
He added however that Kerry planned on Tuesday to "remotely" join the Paris talks, which are aimed at reviewing the international coalition's strategy against the jihadists, also known as ISIL, who have seized swathes of territory in Iraq and Syria.
"The secretary is stable and never lost consciousness, his injury is not life-threatening, and he is expected to make a full recovery," Kirby said in a statement earlier Sunday.
"Given the injury is near the site of his prior hip surgery, he will return to Boston today to seek treatment at Massachusetts General Hospital with his doctor who did the prior surgery."
Kerry had asked local officials in eastern France's Haute-Savoi to organise the trip in the beautiful Alpine region.
"He had expressed a wish, a few days ago, to complete a stage of the Tour de France passing through the Col de la Colombiere. The hill is very well-known for its difficulty, and because he loves France and cycling, he decided to climb it on his bicycle," the local source said.
"He fell accidentally, like all other cyclists have at some point."
Scionzier resident Arfaoui Aymen, 29, reported seeing "police everywhere" following the accident.
Kerry was flown by helicopter to the Geneva University Hospital after the accident which occurred around 9:40 am (0740 GMT).
"Paramedics and a physician were on the scene with the secretary's motorcade at the time of the accident," Kirby said.
Another State Department official, speaking on condition of anonymity, said Kerry fell after hitting a kerb.
Kerry held talks Saturday in Geneva with his Iranian counterpart Mohammad Javad Zarif as part of international efforts to secure a landmark nuclear deal ahead of a June 30 deadline.
The talks did not go into a second day as planned after Tehran rejected a key Western demand for site inspections.
Often on his bike There are heightened diplomatic moves to try to end a 12-year international standoff and put a nuclear bomb beyond Iran's reach.
The lanky Kerry has become a recognisable figure as a regular globetrotter since taking office as Secretary of State in February 2013.
During breaks from negotiations, he has often headed out of his hotel to ride his bike - which he usually brings along on his foreign missions - accompanied by a posse of security guards.
Kerry had been scheduled to leave late Sunday afternoon for Madrid.
Spain and the United States were to formalise an agreement under which Spain will host a permanent force of 2,200 US Marines for deployment on missions to Africa.
"The secretary very much regrets not being able to visit Spain to meet with one of our close allies for discussions on a range of issues, as well as being unable to attend the counter-ISIL coalition ministerial meeting on Tuesday in Paris in person," Kirby said.
Kerry's British counterpart Philip Hammond meanwhile expressed his concern.
"@JohnKerry sorry to hear of your #Geneva accident. Hoping you make a speedy recovery and are back on the road soon," the foreign secretary tweeted.