Former US President George H.W. Bush's condition has improved enough for him to be moved out of the intensive care unit and into a regular room at the Houston hospital where he was admitted more than a month ago, a spokesman said on Saturday.

Bush, 88, was admitted to Methodist Hospital on Nov. 23 with bronchitis, and he was moved into the intensive care unit last Sunday after suffering a number of medical complications, including a persistent fever.

"The Bushes thank everyone for their prayers and good wishes," the family said in a statement from the former president's spokesman, Jim McGrath.

McGrath said on Friday that Bush's condition was improving and that he was even singing at times in his communications with doctors and nurses.

Bush, the 41st US president, was in office from 1989 to 1993 and is the father of former President George W. Bush. In a political career spanning four decades, Bush, a Republican, also served as a congressman, ambassador to the United Nations, envoy to China, CIA director, and vice president for two terms under Ronald Reagan.

Bush has lower-body parkinsonism, which causes a loss of balance, and has used a wheelchair for more than a year.