WASHINGTON — The Trump administration on Thursday announced the release of two Americans imprisoned overseas and said it had intensified demands for a third, amid global fears that the coronavirus could quickly spread among detainees and result in deaths.

Amer Fakhoury, a Lebanese-born naturalized American citizen, was headed to his home state, New Hampshire, from Beirut, where he had been detained for months on decades-old charges of torturing Lebanese prisoners.

“Any time a U.S. citizen is wrongfully detained by a foreign government, we must use every tool at our disposal to free them,” said Senator Jeanne Shaheen, Democrat of New Hampshire, as Mr. Fakhoury flew back to the United States on a military aircraft. “No family should have to go through what the Fakhoury family has gone through.”

Separately, Michael R. White, a U.S. Navy veteran and cancer patient, was released from an Iranian prison, where he had been held since July 2018, the State Department announced. Mr. White, of Imperial Beach, Calif., was freed on a medical furlough.