WASHINGTON — The Trump administration said Tuesday that it is pulling almost all U.S. Agency for International Development workers off the job and out of the field worldwide, moving to all but end a six-decade mission to shore up American security by fighting starvation, funding education and working to end epidemics.

The largest U.S. government worker union and an association of foreign service workers sued the Trump administration on Thursday in an effort to reverse its aggressive dismantling of the U.S. Agency for International Development.