North Dakota's state prison warden says cell phones have not been a big problem at the penitentiary and officials want to keep it that way.

Warden Tim Schuetzle said the only problems with contraband cell phones he can recall in the state prison system in recent years involved two prison officers, and both were fired.

In one incident about two months ago, an officer at the Missouri River Correctional Center, a minimum-security prison in south Bismarck, was allowing inmates to use his personal cell phone, Schuetzle said.

"We discovered an inmate arranging for a contraband drop," the warden said. The officer was fired, he said.

"We don't allow any cell phones in the facility," Schuetzle said. "We tell staff, 'You have to keep your cell phone in your car.'"

A number of years ago, an officer at the penitentiary was suspected of bringing in tobacco for inmates, Schuetzle said.

"We stopped him and searched him and found tobacco and two cell phone batteries," Schuetzle said. The officer said he was bringing the batteries inside to keep them warm, but they did not match the cell phone in his car, Schuetzle said.

"He also was terminated," the warden said.

Inside the prison, "in all our searches, if there was a cell phone here, we haven't found it," Schuetzle said Friday.

Other states have passed legislation to punish guards and visitors who provide cell phones to inmates. Maryland and Virginia have become the first states to train dogs to sniff out phones hidden in socks and books and under mattresses.

"There are technologies available to detect when a cell phone call is made out of a facility," Schuetzle said. "It is something we would consider doing in a new facility, but in this facility it would be cost-prohibitive."

The idea of using dogs might be considered, he said.

Attorneys for prisoners and their families say inmates may use contraband cell phones because collect calls home are too expensive.

Corrections officials say cell phones could be used to plan escapes or hits on other inmates.

Right now, Schuetzle said, "It's not a big problem for us, but it's certainly a concern."