WASHINGTON — Russian officials in August held up the evacuation from Moscow of a sick American military attaché to a hospital in Germany in the latest episode of a long-running campaign of harassment against American diplomats in Russia.

Diplomatic protocols allow for the fast evacuation of diplomats facing medical emergencies. But the departure of the plane sent to evacuate the attaché was delayed for hours for no apparent reason despite protests from embassy officials and the State Department in Washington, according to several Trump administration officials who spoke on the condition of anonymity to discuss a sensitive diplomatic issue that some other officials prefer to play down.

The Russians eventually relented, and the American, a uniformed officer, was safely evacuated, the officials said.

While State and Defense Department officials confirmed there was a medical incident in Russia, they declined to identify the officer and would not provide any details of the case or why he was being evacuated.