The new U.S. ambassador to the United Nations arrived Thursday in New York, where she said she looked forward to engaging with allies and partners to tackle the many challenges the world faces.

"The United Nations is the most important forum for bringing people and countries together, and I take that seriously as a U.S. diplomat," Linda Thomas-Greenfield told reporters.

A day after being sworn in by Vice President Kamala Harris, the ambassador arrived to a busy first month - the United States takes over the rotating presidency of the U.N. Security Council on March 1.

She presented her credentials to U.N. Secretary-General Antonio Guterres and told reporters she was "thrilled" to be at the U.N. after a 35-year career in the foreign service.

"We are clear-eyed about the difficult work that needs to be done, from elevating human rights to reforming the U.N. itself, to addressing conflicts old and new around the world, and we look forward to engaging our allies and our partners to get it done," Thomas-Greenfield said. "After all, we are stronger when we are working together."

She is the fifth consecutive female ambassador Washington has sent to the world body. President Joe Biden has also elevated her post to Cabinet level.

Thomas-Greenfield will have her work cut out for her at the United Nations. The Trump administration was largely indifferent to the organization and pulled back its support - both financial and diplomatic - on several fronts. Biden has vowed to reengage with the world body and embrace multilateralism.

The Senate confirmed the ambassador on Tuesday, 78-20.