Senator Bernie Sanders was hospitalized Wednesday and treated for an artery blockage after suffering from chest pains, his campaign confirmed. The presidential hopeful is canceling forthcoming events and appearances until further notice.

“During a campaign event yesterday evening, Sen. Sanders experienced some chest discomfort. Following medical evaluation and testing he was found to have a blockage in one artery and two stents were successfully inserted,” Sanders senior adviser Jeff Weaver said in a statement. “Sen. Sanders is conversing and in good spirits. He will be resting up over the next few days. We are canceling his events and appearances until further notice, and we will continue to provide appropriate updates.”

Sanders tweeted an update later on Wednesday, writing, “Thanks for all the well wishes. I’m feeling good. I’m fortunate to have good health care and great doctors and nurses helping me to recover.”

“None of us know when a medical emergency might affect us,” he went on. “And no one should fear going bankrupt if it occurs. Medicare for All!”

Sanders’ last outing was Tuesday night at the Las Vegas shooting memorial. Sanders was scheduled to hold events on Thursday on campuses in Riverside, Bakersfield and Fresno, as he courts the Latino vote in California. He was also scheduled to have a town hall on Friday at the University of Southern California, and an appearance at an SEIU candidate summit in Los Angeles on Friday afternoon.

Sanders, 78, is the oldest candidate currently in the Democratic primary. Former Vice President Joe Biden is 76, and Massachusetts Sen. Elizabeth Warren is 70. Donald Trump is the oldest president to take office at 73 years old.

Warren was among his Democratic primary competitors sending well wishes on social media to Sanders. “I hope to see my friend back on the campaign trail very soon,” she wrote on Twitter.

Biden also extended sympathies to the Sanders family, writing, “Anyone who knows Bernie understands what a force he is. We are confident that he will have a full and speedy recovery and look forward to seeing him on the trail soon.” Kamala Harris echoed that sentiment, adding, “If there’s one thing I know about him, he’s a fighter.”

The Sanders campaign raised $25.3 million in the third quarter, the most any Democrat has announced so far. The campaign released its first TV ad on Wednesday, but a $1.3 million ad buy in Iowa was reportedly postponed.