US Ambassador to the United Nations Nikki Haley reportedly announced Monday that the United States and almost 40 other nations would not take part in the talks on an international treaty to ban nuclear weapons.

President Barack Obama's administration also objected the talks, which the General Assembly voted to approve in December, and nuclear powers Russia and China also are not participating. United Kingdom Ambassador Matthew Rycroft said his country also would not attend the talks because the country does not believe that the discussions will lead to effective progress on global nuclear disarmament.

Accompanied by ambassadors from about 20 nations, including nuclear powers the United Kingdom and France, Haley revealed the intention not to attend the talks, which began Monday, in personal terms.

As a mom and daughter, "there is nothing I want more for my family than the world with no nuclear weapons," the former South Carolina governor said. "But we have to be realistic."

"Is there anyone that believes that North Korea would agree to a ban on nuclear weapons?" Haley asked.

President Donald Trump told Reuters last month that a nuclear-free world will be ideal, but otherwise, the United States should be "at the top of the pack."

Treaty supporters say the risk of a nuclear detonation is higher than at any time since the end of the Cold War. But Haley said of the foreign officials joining the discussions and begs to differ, "you have to ask yourself, are they looking out for their people? Do they really understand the threats that we have?"

If adopted, the treaty would outlaw the use, possession, and development of nuclear weapons and set up their eventual elimination.