WASHINGTON — Kimberly Guilfoyle resigned as U.S. ambassador to Greece on Tuesday after the White House publicly said it had asked her to step down amid allegations of improper conduct. President Donald Trump said he was dissatisfied with what he had read about the accusations and confirmed she would no longer represent the United States in Athens. Guilfoyle announced her resignation on X within two hours of the White House statement. She called the allegations false and said she would “vigorously defend” her name, reputation and integrity. The allegations, reported in recent weeks by The Wall Street Journal and other outlets, include claims that Guilfoyle accepted improper gifts and services, threatened a Greek official and offered to use her influence in the administration in exchange for help paying a $100,000 credit-card bill. The Journal also reported that she promoted the interests of a Greek construction and energy company and allowed its lobbyist into private diplomatic meetings. The claims have not been established as fact. Guilfoyle’s attorneys have denied wrongdoing. They said the money she sought from a Trump donor was payment for speaking engagements and public appearances that took place before her ambassadorial nomination. They also said she followed State Department guidance and travel rules before taking private-plane trips. The State Department’s inspector general was looking into the allegations, a U.S. official said, but it was unclear whether a formal investigation had begun. The department declined to comment on a possible inquiry. House and Senate Democrats have called for an investigation. The White House’s move followed days of mounting scrutiny. Trump said Tuesday that Guilfoyle had been doing a good job in Greece, but added: “We didn’t like what we were reading.” Earlier, Secretary of State Marco Rubio had publicly defended her as a “strong ambassador,” then said he could not verify the allegations and would not treat unconfirmed reporting as gospel. Guilfoyle’s departure leaves the administration to fill a high-profile diplomatic post at a time when Greece’s location gives it strategic importance in southeastern Europe and the eastern Mediterranean. The country is also a potential route for liquefied natural gas moving into the Balkans and beyond, making energy a key part of the U.S.-Greek relationship. Greek opposition lawmakers had urged their government to summon Guilfoyle to answer the allegations. Former deputy foreign minister Sia Anagnostopoulou called the matter one of “national dignity.” Foreign Minister Giorgos Gerapetritis said Guilfoyle had been treated like other ambassadors and that a formal summons was not necessary. A former Fox News host and California prosecutor, Guilfoyle was previously married to Gavin Newsom, now California’s governor, and later became engaged to Donald Trump Jr.