U.S. President Donald Trump defended his daughter, White House adviser Ivanka Trump, on Monday after she raised some eyebrows over the weekend by taking his place at a table with world leaders at a G-20 meeting.

She briefly sat in her father's chair at the global gathering in Hamburg during a closed-door session on African development as the World Bank president spoke. Her appearance prompted a string of reactions on Twitter and caught the attention of the German media and other outlets.

Early on Monday, Trump called the arrangement "very standard" in a tweet where he also noted that German Chancellor Angela Merkel, who was hosting the G-20 summit, agreed.

@realDonaldTrump When I left Conference Room for short meetings with Japan and other countries, I asked Ivanka to hold seat. Very standard. Angela M agrees!

@realDonaldTrump If Chelsea Clinton were asked to hold the seat for her mother, as her mother gave our country away, the Fake News would say CHELSEA FOR PRES!

Chelsea Clinton responded to Trump's tweets, saying, "It would never have occurred to my mother or my father to ask me."

@ChelseaClinton Good morning Mr. President. It would never have occurred to my mother or my father to ask me. Were you giving our country away? Hoping not.

Merkel had dismissed the move at a news conference after the G-20 ended. "Ivanka belongs to the U.S. delegation," Merkel, who has worked with her on various issues, said last week.

Nikki Haley, the U.S. ambassador to the United Nations, also defended Ivanka, saying on Sunday that the president's daughter had often sat in on meetings with her and Trump, especially those regarding women and business.

Ivanka Trump ran a clothing and jewelry business before taking a formal job at the White House after her father took office in January. She has made women's issues one of her signature policy areas.

At the G-20, she also took the spotlight at a separate event alongside World Bank President Jim Yong Kim and other world leaders to launch a public-private loan program aimed at boosting female entrepreneurs in developing countries.

Lawrence Summers, a former World Bank official and economic adviser under former Democratic president Barack Obama, said it was rare for government heads to leave during major summits and that, when they must, foreign ministers or other very senior government officials normally fill in.

"There is no precedent for a head of government's adult child taking a seat," he wrote in the Washington Post on Sunday. "There is no precedent for good reason. It was insulting to the others present and sent a signal of disempowerment regarding senior government officials."

—CNBC contributed to this report.