US ex-president George H.W. Bush fell and broke a bone in his neck, his spokesman said, following reports that the former leader had been hospitalized yet again.

"His condition is stable -- he is fine -- but he'll be in a neck brace," Bush spokesman Jim McGrath tweeted.

The 91-year-old former president, who fell Wednesday morning in Kennebunkport, Maine, was being treated at a hospital in the city of Portland some 30 miles (50 kilometers away), CNN reported.

"We are not expecting a long stay," McGrath told the channel.

On Twitter, McGrath said that Bush "fell at home in Maine today and broke a bone in his neck."

The oldest of the four living former US presidents, Bush, who uses a wheelchair, has seemed frail in recent public appearances.

In December the 41st president was admitted to a Texas hospital for breathing problems.

He was treated at the same Texas facility in November 2012 for bronchitis, spending nearly two months in the hospital.

The patriarch of one of America's most prominent political dynasties is father to former US president George W. Bush.

Another son, Jeb, the former governor of Florida, jumped into the 2016 presidential race last month, announcing his bid for the Republican nomination.