A natural gas leak closed the Windsor-Detroit Tunnel for several hours Monday morning.

Windsor Fire and Rescue Services officials say a four-inch natural gas line was struck. The tunnel reopened about 11:45 a.m.

City of Windsor engineer Mario Sonego says construction workers came across the gas line during the tunnel plaza expansion at Goyeau Street and Wyandotte Street East.

Union Gas workers repaired the line and stopped the gas flow around 11:30 a.m.

Five different gas mains had to be shut down to relieve pressure. About 100 customers were without natural gas during the process.

 All U.S.-bound traffic was being directed to the Ambassador Bridge as crews worked to fix the problem. Canada-bound traffic was still able to use the tunnel.

Windsor police were re-directing police away from the area at Wyandotte and Windsor Avenue, starting just after 9 a.m.