A global positioning system that tracks sex offenders failed in several states on Tuesday, leaving authorities blind to the real-time movements of thousands of offenders for most of the day, Wisconsin prison officials said Wednesday.

The system's manufacturer, Boulder, Colo.-based BI Incorporated, confirmed that the outage affected 16,000 offenders nationwide, Wisconsin Corrections Department spokeswoman Linda Eggert said. A message at BI's offices wasn't immediately returned.

The outage began around 9 a.m. and was back up about 11 hours later, Eggert said.

Wisconsin prison officials had local police and probation agents detain about 140 offenders until the system was back up and their whereabouts during the outage could be confirmed. Wisconsin offenders were never aware they weren't being tracked, Eggert said.

During the outage, the state Corrections Department contacted offenders who were still on extended supervision and told them to report to their probation agents. The offenders were then transported to local jails.

"Due to a system failure beyond our control, we faced a challenging and unprecedented event for our Electronic Monitoring Center," Wisconsin Department of Correction Secretary Rick Raemisch said in a statement.

But thanks to the agency's emergency plan and cooperation from local law enforcement, "the situation was managed safely and efficiently with the number one priority being public safety," he said.

Eggert didn't know how many apprehension requests went out Tuesday or how many of the offenders remained in custody as of Wednesday afternoon.