HOUSTON - Former U.S. president George H.W. Bush has been hospitalized for days with a lingering cough that has drawn concern, officials said on Thursday.

The 88-year-old Bush, who remains at Houston's Methodist Hospital for seven days, has bronchitis, but his condition is not considered life-threatening, The Houston Chronicle quoted Bush's chief of staff, Jean Becker, as saying in an online report.

"President Bush is in the hospital," Becker said. "We have kept this quiet out of respect for him."

Bush has been in and out of Methodist Hospital for a few weeks, and was most recently admitted the day after Thanksgiving, according to the report.

He was visited there on Sunday by his son, former U.S. president George W. Bush and Laura Bush, his daughter-in-law.

"His big problem is a chronic cough he can't get rid of, so he' s back at Methodist," Becker said. "This is not a life-threatening illness."

Becker said there were some earlier concerns that the cough would turn into pneumonia, but it has not.

Bush is expected to be released this weekend, she added.

Bush served as the 41st president of the United States from 1989 to 1993.