YELLOWSTONE NATIONAL PARK (AP) - Construction of jail cells at the park's new $5.3 million justice center has been delayed indefinitely because of rising project costs, officials said.

Work began this summer on a new center that will replace a cramped courthouse at Mammoth Hot Springs.

Vickie Roseberry, Yellowstone's manager for the project, said rising construction costs forced a delay in building the jail portion of the project, and it was not clear when the jail cells would be built.

"It's going to take some time," Roseberry said.

As a national park, Yellowstone has its own court system and federal judge to deal with violations in the park. The judge is responsible for all initial appearances for defendants charged with felonies and misdemeanors. Some cases eventually move to federal courtrooms in Cheyenne or Casper.

For years, judicial work has been done in a 7,000-square-foot building built in 1903 and used first as an engineer's office. It was converted for use as a federal court in 1980.

When court is in session, the 262-square-foot courtroom barely has enough room for the judge, a ranger, lawyers and the accused. The building has no holding cells.

Complicating matters is that the number of court cases in Yellowstone over the past 25 years or so has quadrupled. Last year, a record number of people was arrested in the park.

In 2004, the Park Service proposed a new Yellowstone Justice Center to be built at Mammoth.

The building, with two floors and a basement, would include a courtroom, judge's chambers, interview rooms and offices for the U.S. District Court, the Park Service and the U.S. Marshals Service.

Work on the building began five months ago and is expected to be finished in October 2008, Roseberry said.

Without the detention wing, though, defendants will continue to be held in temporary holding cells inside a separate 1911 building at Mammoth that doesn't meet safety or seismic codes or holding facilities elsewhere in Montana or Wyoming, the Park Service has said.