Another person was seriously wounded in the incident late Tuesday, as Marois was hustled offstage by bodyguards. She later returned to the podium, visibly shaken but unharmed, and quickly concluded her remarks.

The shooting came as media projections showed Marois's Parti Quebecois (PQ) ousting Premier Jean Charest's Liberals from power, which would make Marois, 63, the French-speaking Canadian province's first female prime minister.

The alleged gunman was quickly arrested after firing a rifle into the crowded concert hall in the provincial capital Montreal, police said.

"This is a homicide investigation. The death was confirmed at the scene. The motive is unknown at this time," the Montreal police said on Twitter.

Caught on camera during the arrest, the alleged gunman shouted "the English are waking up," apparently referring to fears of Francophone domination of the English-speaking minority in an independent Quebec.

The Parti Quebecois favors independence from mostly English-speaking Canada, but is not expected to immediately pursue secession.

Shortly before the shooting, however, Marois had said that "the future of Quebec is to be a sovereign country."

The party's victory came after allegations of corruption and months of nightly student protests over a planned tuition hike, with polls showing widespread dissatisfaction with nine years of Liberal rule.

Several polling stations were still reporting, but it appeared that Marois's party will lead a minority government, having secured around 32 percent of the vote, only narrowly ahead of the Liberals.

But Charest's career appeared to be in ruins after he was beaten in his hometown of Sherbrooke by PQ candidate Serge Cardin, who secured 42.41 percent of votes to the incumbent's 34.7 percent.

Despite a strong record on the economy Charest, only the second Quebec leader since the 1950s to have served three terms, failed to excite voters. Turnout was strong, with nearly 6 million voters casting ballots for 125 lawmakers.

Quebec twice rejected independence in 1980 and 1995, but federalists only narrowly won the last referendum.

Marois has said she will only hold a third referendum on independence if a win is assured, which is unlikely, given that barely one in three Quebecers currently support secession.