Democratic presidential candidate Bernie Sanders has announced he will be canceling his events "until further notice" after he was hospitalized and underwent a medical procedure for an artery blockage.

"During a campaign event yesterday evening, Sen. Sanders experienced some chest discomfort," his campaign said in a statement to ABC News. "Following medical evaluation and testing he was found to have a blockage in one artery and two stents were successfully inserted." 

Sanders, the Democratic field’s oldest candidate, sometimes jokingly refers to his age at town halls and other events, especially when interacting with younger participants. His aides have tried to project him as a candidate with energy levels that surpassed his 2016 presidential campaign.

He is one of three candidates over age 70 in the Democratic primary, which has spurred debate over whether the party should rally behind a new generation of political leaders.

His health scare is certain to revive that discussion in the weeks before the next presidential debate this month.

His senior adviser, Jeff Weaver, said in a statement that the Vermont Senator "is conversing and in good spirits."

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Sanders is one of 12 candidates who have qualified for the next Democratic debate, slated for Oct. 15. 

His campaign manager, Faiz Shakir, was on a telephone call with supporters Tuesday night but didn't mention any health concerns about the candidate.

Shakir said the "state of the campaign is strong" and he played up Sanders' strong fundraising total for the third quarter.

Sanders recently canceled some appearances in South Carolina because he lost his voice. The campaign said at the time he felt fine.

The Associated Press contributed to this report.