US First Lady Jill Biden has attended a ceremony at the UNESCO headquarters in Paris to mark her country's return to the UN agency following a five-year absence.

The US left the United Nations Educational, Scientific and Cultural Organization in 2018 under former President Donald Trump's administration.

After President Joe Biden's administration expressed its intention to rejoin, the US membership was fully reinstated on July 10 with member states' approval.

In her speech at Tuesday's ceremony, she stressed the US commitment to contributing to the spread of education in cooperation with other nations.

She said, "Some of the biggest challenges of our time cannot be solved in isolation. President Biden understands that if we hope to create a better world, the United States can't go it alone, but we must help lead the way. That's why we're so proud to rejoin UNESCO."

She said, "Education is a powerful key to that future. It changes us, so we can go on to change our world together. Together, let's empower the next generation of thinkers and dreamers and doers, helping them unleash their possibility."

In addition to UNESCO, the Biden administration has rejoined a number of international entities that the US left under former President Trump, including the Paris Agreement on climate change.