Aides had included guidance in Trump’s talking points for the call to Putin stating: “DO NOT CONGRATULATE,” a senior administration official said on Wednesday.

The document had been accessible only to a select group of aides, two officials said. They also said there now is an internal probe of the leak but provided no other details. The officials spoke on the condition of anonymity to discuss sensitive internal deliberations. 

The White House is not formally acknowledging the veracity of the presidential guidance first reported by The Washington Post.

The statement on Wednesday about a possible firing was an unusual threat by the White House and an indication of the seriousness with which the administration is treating the latest breach, the officials said. 

President Donald Trump and Chief of Staff John Kelly are both angry over the disclosure, the officials said, especially because of the small circle of distribution.

Other leaks of classified material - including partial transcripts of Trump’s calls with foreign leaders - have not garnered specific warnings of termination or criminal action. 

It was not clear whether the document in question was classified, but it was included with other classified papers.

It also was unclear whether Trump, who prefers oral briefings, had read the talking points prepared by his national security team before Tuesday’s call. 

National Security Adviser H.R. McMaster briefed the president in person before the conversation in the White House residence.

The leak further cast doubt on McMaster’s longevity in the top foreign policy post. The guidance for Trump had been prepared by his staff. 

Trump has been moving toward replacing McMaster on the advice of Kelly and Secretary of Defence James Mattis, but has not settled on timing or a successor.

Trump’s call of congratulations to Putin drew bruising criticism from members of his own party even before the revelation that he was advised against it.

“An American president does not lead the free world by congratulating dictators on winning sham elections,” said Arizona Republican Senator John McCain.

McCain chairs the Senate Armed Services Committee and has pressed the Trump administration to respond aggressively to Russia’s interference in the US presidential election.

Iowa Republican Senator Charles Grassley, R-Iowa, said Wednesday he wouldn’t comment specifically on Trump’s action, but he told CNN: “I think Putin’s a criminal. What he did in Georgia, what he did in Ukraine, what he did in the Baltics, in London...That’s a criminal activity.

“ I wouldn’t have a conversation with a criminal.”

The call was the latest indicator of Trump’s personal reluctance to publicly criticise Putin. The White House said Trump did not raise Russia’s meddling in the US elections or its suspected involvement in the recent poisoning of a former spy in Britain in the call with Putin. 

Trump also said he and Putin might meet “in the not too distant future” to discuss the arms race and other matters. He said that during their hoped-for meeting the two men would likely discuss Ukraine, Syria and North Korea.

White House press secretary Sarah Huckabee Sanders defended Trump’s call and noted that President Barack Obama made a similar call at the time of Putin’s last electoral victory.

“We don’t get to dictate how other countries operate,” Sanders said.

Florida Republican Senator Marco Rubio called the leak a “bigger outrage” than Trump’s congratulations for Putin.

“If you don’t like President resign, but this ongoing pattern of duplicity holds potential for serious damage to the nation,” he said on Twitter.

Trump’s call came at a period of heightened tension after the White House imposed sanctions on Russia for its interference in the 2016 US election and other “malicious cyberattacks.” 

Sanders insisted that the administration has scolded Putin at the appropriate times.

“We’ve been very clear in the actions that we’ve taken that we’re going to be tough on Russia, particularly when it comes to areas that we feel where they’ve stepped out of place,” she said.

The Kremlin said in a statement that Trump and Putin spoke about a need to “coordinate efforts to limit the arms race” and for closer cooperation on strategic stability and counterterrorism.

“Special attention was given to considering the issue of a possible bilateral summit,” the Kremlin statement said.

No details were released about the timing or location of a possible meeting with Putin, which would be the third since Trump took office in January 2017. 

They met on the sidelines of an international summit in Germany last summer and again more informally at another gathering of world leaders in Vietnam in November.