COLUMBIA - South Carolina Gov. Mark Sanford has been hiking along the Appalachian Trail, a spokesman said tonight, explaining an absence of several days.

The lieutenant governor, other officials and even his wife said earlier today that they didn't know where he was, leading critics to question who was in charge of South Carolina.

"I cannot take lightly that his staff has not had communication with him for more than four days, and that no one, including his own family, knows his whereabouts," said Lt. Gov. Andre Bauer. Bauer said he'd been rebuffed by the governor's staff when he tried to find out where Sanford was.

The Republican governor left town Thursday, spokesman Joel Sawyer said, with plans to hike the trail, which passes through 14 states, but not South Carolina. Sawyer said he didn't know where exactly Sanford was along the 2,200-mile trail and declined to discuss Sanford's travel arrangements or who, if anyone, was hiking with him. The governor is expected back later this week.

"He's an avid outdoorsman," Sawyer said. "Nobody's ever accused our governor of being conventional."

Sanford, who's also chairman of the Republican Governors Association, earned a reputation as the nation's most vocal anti-bailout governor by refusing $700 million in federal stimulus money for schools until he lost a court battle earlier this month.

"He's just up there to kind of clear his head after the legislative session," Sawyer told The Associated Press in an interview.

Sawyer said if there were an emergency the office would consult with other state officials before making any decisions.

"We knew he would be difficult to reach, and that he would be checking in infrequently," Sawyer said in a statement.

First lady Jenny Sanford said earlier Monday that she had not spoken with her husband for several days, including Father's Day. The Sanfords have four sons.

"He was writing something and wanted some space to get away from the kids," Mrs. Sanford told The Associated Press while vacationing at the family's Sullivans Island beach house. She said she didn't know where he was but wasn't concerned.

A message left for her wasn't immediately returned after the governor's hiking plans were disclosed.

Law enforcement officials who handle his security declined to comment and Sawyer wouldn't say whether Sanford had a security detail with him. Sanford is known for taking walks and runs without security, but flight logs show he seldom leaves the state without it.

Sanford typically is open about his whereabouts, and his office has in the past made no secret of time spent on vacation or out of state.

But politicians, including the lieutenant governor, said they did not know Sanford was taking time away from his office. Bauer said he had not been put in charge.

Sanford's critics were quick to criticize the governor.

"It's one thing for the boys to go off by themselves, but on Father's Day to leave your family behind? That's erratic," said Senate Minority Leader John Land, D-Manning.

Sanford's unannounced absence was a cause for concern because the National Guard and the state's top law enforcement agencies report to him, Land said.

"And when those officials can't get in touch with the commander, it's really weird. That's not responsible," he said.

Sen. Jake Knotts, a Lexington Republican and a persistent Sanford critic, said the state needs to know where its governor is.

"The way things are in the world today and homeland security, we need the governor to be fingertips away," Knotts said. "Somebody's got to be in charge."