Two Democratic candidates have each picked up the endorsement of a local union in the race for mayor.
NY1 has learned the city's Transport Workers Union, TWU Local 100, will support Democrat William Thompson.
The union, which represents bus and subway workers, also supported Thompson when he ran for mayor in 2009.
A formal announcement is expected to come on Tuesday.
Meanwhile, Local 831, the union representing city sanitation workers, announced it is backing Christine Quinn.