The United States-funded news service Radio Free Asia said on Friday that it has closed its office in Hong Kong because of concerns about the city’s recently enacted national security law that targets so-called foreign interference. Hong Kong’s new national security law, which was passed with unusual speed earlier this month, raised “serious questions about our ability to operate in safety,” the broadcaster’s president and chief executive, Bay Fang, said in a statement. Radio Free Asia said that it had relocated some employees from Hong Kong to Taiwan, the United…