BOSTON - Presidential candidate and U.S. Senator Bernie Sanders has announced he is opening his first official campaign office in Massachusetts this Saturday, Jan. 9, in Charlestown.

Sanders' Massachusetts headquarters will be located at 89 Cambridge St. in Charlestown.

On hand for Saturday's opening will be Democratic State Senator Jamie Eldridge, who will officially endorse Sanders at that time, the campaign said. The ceremony will take place at 10 a.m.

Sanders was introduced at a rally in Worcester Saturday by Democratic Worcester State Rep. Mary Keefe, who said Sanders' candidacy "comes down to working for change and not being afraid to challenge the status quo."

Sanders, who gave as stump speech to just under 3,000 people in Worcester and about 1,900 in Amherst on Saturday, trails Democratic front-runner Hillary Clinton in recent polls, but told the crowds he was within "striking distance" in Iowa, where the first in the nation caucus will be held, and that he would win New Hampshire, which holds its primary soon after.