WASHINGTON — The visa applications of hundreds of international students seeking to work in the United States this summer are languishing at the United States Citizenship and Immigration Services, where increased processing times have left students stranded and university leaders struggling with the fallout.

Students have written petitions and panicked letters to leaders of some of the top universities in the country as their internship start dates have come and gone with no word from the federal government.

Recent graduates of the Columbia University Graduate School of Journalism are pushing back start dates for internships and relying on their parents for day-to-day expenses. Students at Princeton have had job offers rescinded, and have been forced to return home for the summer. At Dartmouth College, students reported losing money they spent for housing and flights to live and work in other states. At Yale, students scrambled to enroll in a newly created course that would allow the university to approve their summer employment.

“Every morning I wake up with anxiety, wondering what am I going to do today when I’m supposed to be working,” said Yaling Jiang, 26, a student from China and recent graduate of Columbia’s journalism school, who was supposed to start an internship last Monday at a trade publication run by The Financial Times.