Four Canadian students —one from Quebec, one from Prince Edward Island and two from Nova Scotia — are among the survivors at a Virginia university after shootings Monday morning thatleft at least 33 people dead.

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An officer walks by Norris Hall on the Virginia Tech campus early Tuesday. ((Casey Templeton/Associated Press))

Yoann Re, a student from Quebec, said he spenthours locked inside his dorm room after the shootings started shortly after 7 a.m. ET at the Virginia Polytechnic Institute and State University inBlacksburg.

The gunman first opened fire at the co-ed residence,West Ambler Johnston dormitory, and started shooting again two hours later at an engineering building, Norris Hall.

The death toll climbed throughout the day but by late afternoon, police confirmed that33 people — including the shooter — haddied and about 15 others were injured in what was being called the worst campus shooting in U.S. history.

Re, a tennis player, said he called his parents in Verdun, Que., to let them know he was fine.

It wasn'timmediately clear how manyCanadians attend the 26,000-student university in western Virginia.

Maritime exchange students also safe

The Nova Scotia Agricultural College in Truro said three of its students who were on an exchange to Virginia Tech were also safe.

The school called its students after learning about the shooting, a college official told CBC News.

The three students— two from N.S. and one from P.E.I. — started their exchange in January and are due home on May 10.

The student from P.E.I., 20-year-old Maryella Maynard, contacted her parents to assure them she was safe and had been in lockdown for much of the day.

Her father, Ron, said people had been calling his family to make sure she was safe.

Pierre Couture, a Virginia Tech professor from Quebec, said the shooting made him think about another one in September 2006 at Montreal's Dawson College, when a 25-year-old gunman killed a woman, injured 19 others and then took his own life.

"I think I can relatenow more. Unfortunately these events are shaking up people like me and my wife," Couture said.

Couture said he still didn't know whether any of his students had been injured or killed in the Virginia shooting.

With files from the Canadian Press