Donald Trump and secretary of state Marco Rubio are weighing whether to fire Kimberly Guilfoyle, the US ambassador to Greece, following a string of reports alleging she engaged in improper and possibly illegal conduct in Athens.

Anger at the White House and State Department

A senior US official, speaking anonymously on Sunday, said Trump and Rubio were furious about Guilfoyle's reported conduct and would probably decide this week what action to take, after Monday's federal holiday.

"Trump and Rubio are "extremely pissed off" by Guilfoyle's reported conduct," the official said, adding that a decision was likely within days.

According to the official, Rubio has been particularly angry in part because he visited Athens only last week, where Guilfoyle attended most or all of his events and greeted him with a bear hug even as the allegations were circulating.

What the reports allege

The Wall Street Journal report and subsequent coverage describe a series of accusations against the ambassador:

• •An alleged threat to a host country official
• •Accepting improper gifts and services
• •Offering to use her influence in the administration in exchange for payment of a large credit card bill
• •Telling guests at a reception that the US could undermine the Greek government if it chose to, promoting a Greek construction and energy company, and letting the company's lobbyist into private diplomatic meetings, per the Journal's first report in late September
• •Asking a Trump donor and supporter, in text messages the Journal cited, to pay a $100,000 credit card bill just before her confirmation hearing, in return for access to administration officials - a report published while Rubio was in Athens
• •Being enraged about not being invited to a Greek-themed event at the World Economic Forum in Davos earlier this year, demanding to attend, and boasting of luxury travel to France with energy company executives

The Daily Mail has separately reported that Guilfoyle alienated staff at the US embassy in Athens and pushed the bounds of behavior appropriate for the top US representative to Greece.

Guilfoyle, a former Fox News Channel host and California prosecutor who was once engaged to Donald Trump Jr, has not directly addressed the reports. Her lawyer has said she did nothing wrong, and the US embassy in Athens has tacitly expressed support for her.

Rubio's shifting response

Rubio first defended Guilfoyle, then declined to comment publicly. On Wednesday he said: "Our ambassador has been a strong ambassador here."

On Thursday, before leaving Athens, he berated journalists for asking about the allegations, saying he did not know whether they were true and would not respond if he could not confirm them.

Standing at the foot of his plane as Guilfoyle watched, he accused reporters of treating any sourced claim as established truth, telling them this was not how he treated such reporting and not how his department operated.

Inspector general and calls for scrutiny

A second anonymous US official said the state department's inspector general is looking into the allegations, which first surfaced in the Journal in late September and have multiplied since.

• •The official could not say whether a formal IG investigation had begun; informal inquiries often do not lead to a full investigation, which can result in disciplinary action up to dismissal
• •The state department has declined to comment on a potential IG investigation
• •Democrats including Gregory Meeks, the top figure on the House foreign affairs committee, Jeanne Shaheen on the Senate foreign relations committee and Robert Garcia, House oversight ranking member, have called for an investigation into Guilfoyle

A decision on possible action was expected this week, after Monday's federal holiday, while the inspector general inquiry continues and whether it becomes a formal investigation remains unclear.