May 12 (UPI) — Food and Drug Administration Commissioner Marty Makary has left the administration after 13 months at that post, President Donald Trump confirmed Tuesday.

Makary is leaving the helm of the federal agency that is largely responsible for regulating medical treatments and vaccines, as well as overseeing safety the country’s food supply, the president said.

Trump declined to say whether Makary was fired or had resigned, but acknowledged that he had been facing criticism.

Makary “was having some difficulty,” Trump told reporters in Washington as he was embarking on a trip to China.

“Marty is a great guy. He’s a friend of mine. He’s a wonderful man. And he’s going to be off and the assistant, the deputy, is taking over temporarily until we find him.”

The president called him “a great doctor and he was having some difficulty, but he’s going to go on and he’s going to do well.”

FDA Deputy Commissioner for Food Kyle Diamantas was named acting commissioner, the White House said.

After generating criticism from several corners during a generally tumultuous tenure, Makary ultimately resigned from the FDA job over concerns about the administration’s decision to authorize fruit-flavored electronic cigarettes, multiple sources told The New York Times.

The FDA on Wednesday gave its OK to such e-cigarettes made by Glas, a company based in Los Angeles, after Trump reportedly pushed Makary to move faster to approve the vapes.

Makary objected on the grounds that they appeal to young people, and so could not in good conscience continue in the job, The Times reported.

Before joining the administration, Makary was a Johns Hopkins University cancer surgeon and health policy researcher. During his time in the FDA post, he frequently aligned himself with the “Make America Healthy Again” policies of Health and Human Services Secretary Robert F. Kennedy Jr.

In addition to the disagreement over flavored e-cigarettes, Makary also ran afoul of biotech industry leaders and investors when he defended a decision made by Dr. Vinay Prasad of the FDA’s drug division to restrict access to new several drugs developed for rare diseases.

Makary similarly angered anti-abortion Republicans who sought to have the FDA restrict telehealth prescription of the abortion pill mifepristone, Politico reported.