A magnitude-5.0 earthquake struck at the Ontario-Quebec border region of Canada on Wednesday, the U.S. Geological Survey said, shaking homes and businesses from Canada's capital in Ottawa on south to the U.S. state of West Virginia.
There were no immediate reports of injuries or damage.
The midday quake was felt in Canada and in a number of U.S. states, including Michigan, Ohio, Pennsylvania, West Virginia, Vermont, New Hampshire, New Jersey and New York.
The USGS said the quake occurred at a depth of about 12 miles (19.2 kilometers). The agency initially said the quake had a 5.5 magnitude, but later reduced it to a magnitude-5.0. The quake occurred at 1:41 p.m. EDT (1741 GMT), the USGS said.
The quake came just ahead of the weekend summit of G-20 and G-8 world leaders in Toronto and Huntsville, Ontario.
The tremors, which lasted about 30 seconds, rattled buildings in Ottawa and Toronto, as well as government offices across the Ottawa River in Gatineau, Quebec.
Several buildings in Toronto and the Ottawa region were evacuated.
Chris Cornell, 46, who works in downtown Toronto, said desks and furniture shook as he sat at his desk in a finance office.
Shirley Pelletier, 27, said a prolonged tremor shook bookshelves and caused paintings on walls to shake in her office just outside downtown Toronto.
Residents of a number of states in the Midwest and Northeast reported feeling the earthquake.
In Ohio, people reported the sound of plaster cracking in Cleveland and buildings in Cincinnati gently swaying.
In Cleveland, James Haselden says his office in a renovated 19th century brick building swayed and he heard plastic cracking but saw no damage.
The Pittsburgh Post-Gazette reported on its website that the Canadian quake was felt by some residents in the western Pennsylvania area.
The quake also was felt in New Jersey, where the Bergen County administration building in Hackensack was evacuated after employees reported they felt a tremor.
Bergen County Police Lt. Christine Francois said numerous people in the Hackensack and Englewood areas called police to report earth tremors.
In Michigan, residents from suburban Detroit to Port Huron and Saginaw reported feeling the earthquake.
Detroit police spokeswoman Yvette Walker told The Associated Press that police personnel on the upper floors of the downtown headquarters building reported feeling the quake.
In New York state, people from Buffalo to Albany and north to Massena on the St. Lawrence River said pets were startled and plates rattled when the quake hit.
David French, 53-year-old state worker from Cicero, New York, said he was at his computer inside his home near Syracuse when he felt his chair shake.
"I thought the chair was breaking or something," he said. "I looked over and my filing cabinet was moving."
The quake prompted several calls to state police in the Adirondacks area.
"A little shake, nothing too big," is how Trooper Mark Revette described the temblor. "It happens. We get a couple of these a year."
Kellie Tassone, 40, was at home on Oneida Lake in Cicero.
"My dog picked his head up just before it happened and kind of looked at me," she said. Then the sliding door started to rattle "and the house was shaking."
The USGS said the two largest quakes in western Quebec occurred in 1935 at magnitude-6.1 and in 1732 at a magnitude of 6.2, where it caused significant damage in Montreal.
The agency said earthquakes cause significant damage in the region about once a decade. Smaller earthquakes are felt three or four times a year.
Associated Press writers Thomas J. Sheeran contributed in Cleveland and Dan Sewell in Cincinnati contributed to this report.