ALBANY, N.Y. (AP) — U.S. Sen. Bernie Sanders of Vermont is backing challenger Jumaane Williams over incumbent Kathy Hochul in the Democratic primary for New York lieutenant governor.

Sanders, a Democrat, announced his endorsements on Monday.

As a leading and influential progressive, Sanders' support is a big boost for Williams, a New York City councilman who is trailing Hochul in the polls. The endorsement is also a rare snub of an incumbent.

Williams was an early supporter of Sanders during the 2016 Democratic primary race for president, which Sanders lost to Hillary Clinton.

Sanders also announced that he's endorsing Democrat Zephyr Teachout in the four-way Democratic primary for attorney general.

He made no endorsement in the Democratic primary for governor between incumbent Andrew Cuomo and challenger Cynthia Nixon.