Melania Trump sent in to end the meeting between her husband Russian leader Vladimir Putin when it overran, but she was unable to stop the pair from talking for another hour, according to Secretary of State Rex Tillerson.
The First Lady "failed" in her bid to bring the face-to-face conversation to a close as the US President's team tried to get on with their schedule at the G20 summit in Hamburg, Germany.
President Trump had been due to talk to the Russian leader for 30 minutes, but spent two-hours-and-16 minutes discussing a ceasefire in southwest Syria, Ukraine, the fight against terrorism and cyber-security before the meeting ended.
Mr Tillerson told the Washington Examiner magazine: "Several times I had to remind the president, people were sticking their heads in the door. They even sent in the first lady at one point to see if she could get us out of there, and that didn't work either.
"We went another hour after she came in to see us, so clearly, she failed."
Mrs Trump was pictured greeting Mr Putin with a smile following the meeting and later sat next to him at a dinner at Hamburg’s Elbphilharmonie concert hall.
Earlier that day the former model had been forced to stay inside her residence and tweeted "Thinking of those hurt in #Hamburg protests. Hope everyone stay safe! #G20" as clashes broke out between riot police and anti-capitalist and anti-Trump protesters at the international conference.
Tear gas and water cannons were used to control the crowds of masked activists, who hurled rocks at officers and set fire to buildings.
Authorities said at least 15 officers were injured during the protest that some demonstrators had called "Welcome To Hell".
After the meeting, the Trump administration claimed the US President pressed Mr Putin during a "very robust and lengthy exchange” over Russia’s alleged interference in the US election.
Russia then claimed Mr Trump accepted Mr Putin’s denial of any election meddling - but this was later denied by a US official.
Alongside the different versions of the much-anticipated encounter between the leaders of the world’s two most heavily armed nuclear powers, it appeared the two sides had managed to pull out something of genuine value – a ceasefire in south-west Syria that would be guaranteed by Russia, the US and Jordan.
Mr Tillerson said Russia, an ally of Syrian President Bashar al-Assad, had an interest in seeing stability there.
Though the Secretary of State said details about the ceasefire need to be worked out, Russian officials said their military police would oversee it, with a monitoring centre set up in Jordan.
Mr Tillerson said the understanding is designed to reduce violence in an area of Syria near Jordan’s border and which is critical to the US ally’s security. Jordan’s Petra news agency said it would go into effect on Sunday.
He called the area a "very complicated part of the Syrian battlefield” but said the deal "is our first indication of the US and Russia being able to work together in Syria”.