Toronto Hydro is reporting more between 5,000 and 8,000 people are without power in the downtown core and parts of the east end this morning. Right now the biggest issues are dead traffic lights causing traffic congestion. Remember, if the lights are out road users need to treat the intersection as a four-way stop.

On the TTC side, things are running normally although King station is using emergency back-up power for its lights. Trains are unaffected. Media spokesman Brad Ross says streetcars are also operating but there may be significant traffic delays.

The lights went out shortly after 8:00 just as the morning rush was building. There were reports of people trapped in elevators being rescued by firefighters but so far no injuries have been reported a direct result of the problem.

Toronto Hydro says engineers are working on a fix.

UPDATE: 09:25

Toronto Hydro says it has restored power downtown but is still unaware of the cause. No fix in the east end yet.

UPDATE: 09:52

Power is back on in the east end. If you're still sitting in the dark call Toronto Hydro on 416-542-8000 and report it.

Chris Bateman is a staff writer at blogTO. Follow him on Twitter at @chrisbateman.