KNOXVILLE (AP)-Cracks have been found in East Tennessee interstate highway bridges and they must be repaired quickly.

Transportation officials said Tuesday the Interstate 81 bridges in Greene County will undergo emergency repairs over the next two weekends, forcing detours of traffic increased because of a North Carolina rock slide.

Inspectors found two cracks in a beam on the northbound bridge and one on a southbound bridge beam.

The I-81 northbound bridge over U.S. 11E will be closed at 10 p.m. on Saturday and is expected to reopen about 12 hours later.

The southbound span will close at 10 p.m. on Saturday, Nov. 21, and is expected to be back in service by 10 a.m. Sunday, Nov. 22.

Traffic will be diverted via the exit and entrance ramps across U.S. 11E.