(Reuters) -The Trump administration last week canceled the first bargaining session scheduled with the U.S. Food and Drug Administration's largest workers union since its ability to represent government staff was temporarily restored by a federal court, according one of the union's bosses. U.S. President Donald Trump in March signed an executive order that excluded agencies from collective bargaining obligations that he said "have as a primary function intelligence, counterintelligence, investigative, or national security work." Senior U.S. District Judge Paul Friedman on April 25 issued an injunction to block the executive order from being implemented, pending the outcome of a lawsuit by the National Treasury Employees Union (NTEU), which represents about 160,000 federal employees including as many as 9,000 FDA staff.