The new problems are unrelated to each other; in the case of Mr. Ullah, the agency said its internal controls flagged the expense fraud. But along with many others over the past two years, the scandals have brought intensified scrutiny and criticism to the agency, formerly known as the Broadcasting Board of Governors. Created during World War II to be an objective, trusted source of information in nations where freedom of the press is under attack, the agency has 3,500 journalists who reach more than 345 million people in 100 countries each week.

The United States Agency for Global Media initiated an investigation into the allegedly faked segment at TV Martí “immediately after these concerns about the footage in question were raised,” the agency said in a statement. “As the agency has made clear, we have zero tolerance for failing to honor clear and universally accepted standards of professional journalism. We also owe it to all involved to conduct a thorough and clear investigation to get all of the facts.”

“I take seriously any breach of professional journalistic standards at any U.S.A.G.M. network. I have asked for a thorough and swift investigation,” Mr. Lansing said in an emailed statement. “I expect all U.S.A.G.M. networks to adhere to truthfulness, fairness and accountability in their reporting.”

Mr. Regalado is the son of Tomás Regalado Sr., the director of the Office of Cuba Broadcasting, which oversees Radio and TV Martí. The senior Mr. Regalado was hired last year and said he would help raise the outlet’s professional standards after it came to light that Martí had previously aired multiple broadcasts calling the financier and Democratic donor George Soros, a longtime opponent of authoritarianism, “a nonbelieving Jew of flexible morals” and other slurs.

Results of an investigation into those broadcasts, released in May, found that “the video, radio and web content of Radio Televisión Martí falls far short” of the agency’s ethical standards and stated mission and in a misguided way mixes propaganda with the foreign policy objectives of the United States. Several staff members and contractors were dismissed for their roles in the anti-Soros broadcast.