The announcement marks the third national union endorsement for Bernie Sanders. | Getty Sanders clinches major union endorsement

Bernie Sanders won his biggest union endorsement yet from the Communications Workers of America, whose former president, Larry Cohen, is active in the Sanders campaign.

The endorsement was first reported on Twitter by Andrea Mitchell of NBC News. It will be announced Thursday morning.


The union represents about half a million dues-paying members in telecommunications and information technology, news media, broadcast and cable television, and airlines.

It’s the third national union endorsement for Sanders, who received the backing of National Nurses United in August and the American Postal Workers Union in November. Combined, those unions represent about one million members. But Hillary Clinton has the lion's share of union endorsements from unions representing more than 10 million of the 14.6 million union members in the U.S.

Also Wednesday, Sanders’ campaign tweeted that more than 2 million contributions have been made.

BREAKING: Over 2 million contributions have been made to @BernieSanders. We don't need billionaires $! #FeelTheBern pic.twitter.com/iVMSk7aXWf — People For Bernie (@People4Bernie) December 17, 2015

The Washington Post reported that by the end of 2015, the campaign is projecting to surpass the total contributions President Barack Obama’s reelection effort tallied by the end of 2015. Sanders' focus remains on targeting donors willing to give small sums of money, typically around $30 or less through the Internet.

Hanna Trudo contributed to this report.