WASHINGTON (Reuters) - The U.S. Department of Homeland Security’s top internal watchdog told Reuters on Tuesday he will retire, after he complained about a delay in the release of a report critical of the department’s handling of President Donald Trump’s travel ban.

FILE PHOTO: Homeland Security Inspector General John Roth testifies before a House Oversight of the Transportation Security Administration on Capitol Hill in Washington June 9, 2015. REUTERS/Carlos Barria

Homeland Security Inspector General John Roth, nominated by former Democratic President Barack Obama in late 2013, said in an interview on Tuesday that his last day will be Thursday. He announced his plans to his staff early last week.

Roth said his decision to step down was unrelated to concerns he raised in a seven-page, Nov. 20 letter to members of Congress that revealed for the first time the findings from his office’s inquiry into how U.S. Customs and Border Protection implemented Trump’s initial travel ban in January.

In the letter, Roth said he was “troubled” that senior Department of Homeland Security (DHS) leaders had taken more than six weeks to decide which parts of the report should be made public, and had given it to the Justice Department to decide whether to redact some sections on internal deliberations.

The 87-page report has yet to be released.

In a statement, a DHS spokesman said its employees “conducted themselves professionally, and in a legal manner” in implementing the travel ban.

Roth said that after he leaves, the inspector general office’s deputy, John V. Kelly, will take over temporarily until the president nominates a permanent replacement.

“It was a good run,” Roth said, noting that he has worked in the government since the Reagan era. “It is now time to do other things. This has been coming for awhile.”

Trump’s travel ban of January 2017, restricting U.S. entry by people from certain Muslim majority countries, has been the target of multiple legal challenges. Its initial implementation led to chaos at airports across the United States.

The January ban was blocked by federal courts. Trump later issued two revised versions in March and September. The U.S. Supreme Court is now weighing whether to let the latest version go into full effect after it was partially blocked by lower courts.

In his letter to Congress, Roth said his office did not substantiate any claims of misconduct by customs agents, but that there was little warning before the ban took effect and the department violated court orders in two different instances.

Roth told Reuters he had not heard any updates since he wrote to Congress. “I still remain very concerned,” he said, adding other inspectors general have told him they too were “surprised” by DHS’ handling of the matter.

Presidentially appointed inspectors general serve at the pleasure of the president, although they typically do not step down with a change in administration.

Roth has worked in government since 1987, including as a prosecutor in the Justice Department and more recently as head of the Food and Drug Administration’s Office of Criminal Investigations.