The majority affected were in the 89106 and 89107 zip codes.
UPDATE 5:45 P.M.: Most customers who had been without power had their electricity restored.
UPDATE 5 P.M.: Around 1,500 customers remain without power as of 5 p.m. with the majority in the 89106 zip code.
UPDATE 4:30 P.M.: Power has been restored to Las Vegas police headquarters but about 4,000 customers remain without power.
The majority affected are still in the 89106 and 89107 zip codes.
An outage has knocked out power at Las Vegas police headquarters and University Medical Center is running on backup generators as a result.
NV Energy reported about 4,000 customers are without power Tuesday afternoon in the area around Charleston Boulevard and Rancho Drive, including the 89106 and 89107 zip codes.
The estimated time of restoration is 6 p.m. but that could change.
Temperatures were reported around 100 degrees at the time of the outage.
This is a developing story. Check back to 13 Action News for updates.