The US vice president Mike Pence was caught on camera saying Donald Trump was "unstoppable", during a conversation with Israeli prime minister Benjamin Netanyahu at the World Holocaust Forum in Jerusalem.
Mr Pence said: "We're contending. He's unstoppable, like somebody else I know."
His comments followed another day of the president's impeachment trial in the Senate, and ahead of another hours-long round of damning remarks from the prosecution linking Mr Trump to abuses of power and obstruction of Congress in its investigation of the president putting pressure on Ukraine to find politically damaging information on his 2020 rival Joe Biden.
Meanwhile, Mr Netanyahu faces three indictments of his own ahead of Israel's third national election within a year.
The two men were among a host of world leaders attending a memorial recognising the 75th anniversary of the liberation of the Auschwitz-Birkenau death camps in Nazi-occupied Poland.
Mr Pence's meeting with Mr Netanyahu preceded an announcement that the White House will host the prime minister and his political rival, Benny Gantz, to begin negotiations under the president's proposed "peace" deal, orchestrated by his son-in-law Jared Kushner.
The vice president said the meeting will "continue discussions about a broad range of issues of mutual concern between the United States and Israel, but also about the prospect of peace."
Mr Netanyahu said he plans to discuss with Mr Trump "his ideas on how to advance peace, and to work closely with him to advance that goal".
The plan effectively ignores Palestinians, who have remained outside of negotiations as the US continues its support for the Israeli government. Mr Gantz is Mr Netanyahu's political foe, and has suggested making territorial concessions to the Palestinians, but has not committed to recognising statehood.
Mr Netanyahu said Mr Gantz's inclusion is an effort to achieve "broad consensus" in "the efforts to achieve security and peace, peace and security for the state of Israel."