[Updated at 5:20 p.m.] U.S. Geological Survey has revised the earthquake's preliminary magnitude to 5.0. The USGS initially assigned it a preliminary magnitude of 5.5.
[Updated at 2:55 p.m.] There has been no major damage reported so far from an earthquake that hit Canada today, the city of Toronto said in a press release.
"In our initial assessment, there has been no major damage to City infrastructure. Further investigations are taking place to confirm," the statement said. "The Toronto Transit Commission and Transportation Services have reported that there has been no damage to their infrastructure or interruptions to service.
"The City’s Emergency Operations Centre is up and running in preparation for the G20 so the City is uniquely prepared to respond to the event. We will continue to monitor the situation and will report as necessary."
[Updated at 2:42 p.m.] Barre Campbell, a spokesman for the city of Ottawa, tells CNN that there are no reports of major damage in downtown Ottawa.Campbell said he witnessed self-evacuations of downtown buildings, but that people appear to be headed back into work buildings now.
[Updated at 2:32 p.m.] An operator at the Ottawa Hospital said she felt the quake for about 30 seconds.
Sgt. Marc LaPorte, a spokesman for the Royal Canadian Mounted Police, told CNN that it was a "slight tremor" and there "doesn't appear to be any damage reported to date yet."
CBC also spoke with Kathleen Sullivan who was working on the eighth floor of an office in downtown Toronto when the quake hit.
"It was very peculiar because we could actually see the plants on our window shelf shaking," she told the CBC. "By the time we gathered in the hall and figured out it wasn't our imagination, it stopped. But it was easily a minute of things shaking.
[Updatd at 2:16 p.m.] The quake struck at 1:41 p.m. near the borders of Ontario and Quebec provinces, the USGS said.
It was about 12 miles deep.
[Updated at 2:15 p.m.] CNN affiliate WDIV in Detroit, Michigan is reporting tremors were felt in the metro area of Detroit.
Other tremors have reportedly been felt in New York, New Jersey, Connecticut and Cleveland, Ohio.
CNN affiliate WFSB in Hartford, Connecticut reported that some residents in Connecticut felt shaking. CNN affiliate WMUR in Manchester, New Hampshire reported that residents in New Hampshire also felt the tremors.
[Posted at 2:10 p.m.] An earthquake with a preliminary magnitude of 5.5 struck Wednesday in southern Canada, the U.S. Geological Survey reported Wednesday.
This story is developing. We'll bring you the latest information as we get it.