A stage in northern Mexico where a presidential hopeful was campaigning for a local candidate collapsed after a gust of wind blew through on Wednesday night, leaving at least nine people dead and at least 60 others injured, a state governor said.

The stage collapsed in San Pedro Garza García, a suburb of Monterrey in the state of Nuevo León, during an event attended by the progressive candidate Jorge Álvarez Máynez and other members of the Citizens’ Movement party. The collapse was caused by strong wind, President Andrés Manuel López Obrador of Mexico said on social media.

The wind picked up suddenly as candidates were chanting campaign slogans onstage, videos posted to social media showed. As the stage lighting truss slammed to the ground, people rushed off the stage to avoid getting crushed. Others in the crowd ran away screaming, some holding one another in the intense wind.

Samuel García, the governor of Nuevo León, announced the death toll and injuries to reporters early Thursday, saying on social media that one of those killed was a child. He said earlier that many had been hospitalized with moderate to severe injuries.

The stage, which had been erected on a baseball field, was the site of a campaign event for the Citizens’ Movement party’s candidate for the city’s mayoral election, Lorenia Canavati. The party said that it had canceled all of its candidates’ scheduled events for Thursday after “hurricane-like winds” knocked the stage down.

Mr. Álvarez Máynez told reporters that he had first noticed the strength of the wind when he saw it almost sweep away the drum set belonging to the band that was scheduled to play that night. As the stage collapsed, he and others jumped off, he said.

“It is terrible that the people who came to enjoy a day of celebration, of joy, with us, with the band, are now victims of this tragedy,” Mr. Álvarez Máynez said.

After the collapse, Mr. Álvarez Máynez said on social media that he was “fine,” and that he had been communicating with the state authorities to determine what had happened. Ms. Canavati said that her team was coordinating with the authorities to support the victims.

Mexico’s meteorological service said on Wednesday evening that wind gusts of up to about 43 miles per hour were expected in the country’s northeast and that tornadoes were possible in Nuevo León and nearby states.

Mr. García, the Nuevo León governor, said in a video message that people should take cover from the storm.

“We’re witnessing electric storms. Very strong winds and heavy rain is expected for the next two hours,” he said. “There’s already been a tragedy.”

People across Mexico will cast ballots for the presidency and more than 20,000 local, state and congressional posts on June 2.

Citizens’ Movement, a center-left party founded in 1999, is represented in this year’s general election by Mr. Álvarez Máynez, who has pitched himself as a third-party alternative to the front-runner, Claudia Sheinbaum of the ruling Morena party’s coalition, and the opposition’s Xóchitl Gálvez. One of them will succeed Mr. López Obrador, who cannot run again under the constitution.

Several candidates have been killed during the current election season in Mexico, a country convulsed by cartel violence. There were no reports of violence at the campaign event on Wednesday.