Ivanka Trump stood up and clapped alongside South Korean President Moon Jae-in and his wife as North and South Korean athletes entered the 2018 Winter Olympics' closing ceremony.
President Donald Trump's daughter is leading the US delegation at the ceremony in Pyeongchang, South Korea.
The North Korean athletes waved their own flag alongside South Korean athletes and their flag.
During the opening ceremony, athletes from the North and South marched with the flag of a unified Korean peninsula.
CNN's Paula Hancocks says she only spotted a few unified flags during the closing ceremony.
By contrast, during the opening ceremony, Vice President Mike Pence remained seated as the North and South Korean athletes entered the stadium.
Ivanka Trump is on a four-day visit to South Korea.
Trump met privately with the South Korean President to brief him on economic sanctions against North Korea that the White House released Friday.
"Trump delivered a personal message to President Moon from President Trump about today's North Korea related sanctions announcement at a small meeting at the Blue House. They also discussed the continued effort on the joint maximum pressure campaign against North Korea," a senior administration official said in a statement.
Treasury Secretary Steven Mnuchin said the President's daughter has "been part of the team" as the White House puts pressure on North Korea.
"Ivanka Trump has been briefed on this. ... She had dinner with President Moon and had a private discussion in advance about this occurring and this has been an interagency process," Mnuchin said.
Trump and husband Jared Kushner's security clearance status and access to classified information has come under scrutiny in recent weeks.