The plight of refugees was among the social issues tackled by this year's Pulitzer Prize winners.

Among the prize's arts categories, former refugee Viet Thanh Nguyen won the fiction prize Monday for “The Sympathizer” – an immigrant tale told in a “wry, confessional voice.”

“Hamilton,” the hip-hop stage biography of Caribbean emigrant Alexander Hamilton, won for drama.In journalism.

The Associated Press won the Pulitzer Prize for public service for reporting on abuse in the seafood industry that helped free 2,000 slave laborers, and Reuters and The New York Times shared the breaking news photography award for images of the European refugee crisis.

The Pulitzer Board, in conferring the most prestigious honours in US journalism and the arts on Monday, also honoured the Los Angeles Times for breaking news reporting for its coverage of the massacre by militants in San Bernardino, California.

The AP's prize-winning “Seafood from Slaves” report was an investigation into the mistreatment of workers in Southeast Asia used to supply seafood to American supermarkets and restaurants. The coverage resulted in the freeing of 2,000 slave labourers and sweeping reforms, the board said.

The reporters “found captive slaves, countering industry claims that the problems had been solved,” AP Executive Editor Kathleen Carroll wrote in her nomination letter to the Pulitzer judges.

“US customs records show the (slave-peeled) shrimp made its way into the supply chains of major US food stores and retailers such as Wal-Mart, Kroger, Whole Foods, Dollar General and Petco, along with restaurants such as Red Lobster and Olive Garden,” the AP reported in the series of 10 articles.

This year's announcement at New York's Columbia University marked the 100th anniversary of the Pulitzers, which began in 1917 after a bequest from newspaper publisher Joseph Pulitzer.