NOTE: Interstate-40 westbound has since reopened near Holbrook following the law enforcement incident.
A 53-mile stretch of westbound Interstate 40 is closed east of Holbrook in northeastern Arizona because of a law enforcement situation involving gunfire.
The Arizona Department of Public Safety says at least one trooper was involved but that no troopers or suspects were injured.
Westbound I-40 is closed because of the investigation and the state Department of Transportation says the closure is expected to be extended.
ADOT says westbound traffic is being detoured off I-40 at Sanders and back to I-40 at Holbrook via U.S. 191 and U.S. 180.
The detour is described as more than 100 miles long as of Friday morning.