WASHINGTON • Democratic presidential candidate Bernie Sanders has cancelled campaign events "until further notice" after experiencing chest discomfort that required medical attention to treat a blocked artery.

Mr Sanders, 78, a Vermont senator, is the oldest candidate in the field. Two stents were successfully inserted in his chest, senior adviser Jeff Weaver said. Mr Weaver said in a statement that Mr Sanders is recovering "and in good spirits".

Last month, Mr Sanders cancelled three South Carolina campaign events to rest his voice because he was hoarse.

During the third Democratic debate in Houston, Mr Sanders' voice was raspy and his campaign team said it was the result of a "vigorous campaign schedule".

Mr Sanders is one of three septuagenarians in the Democratic field, along with Mr Joe Biden, 76, and Ms Elizabeth Warren, 70. President Donald Trump, the likely Republican nominee, is 73.

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