Bill Gates said that Elon Musk had gutted the U.S. Agency for International Development, resulting in the deaths of children in some of the world’s poorest countries.

The new talks between Sam Altman and OpenAI’s board were the latest twist in a fast-moving drama at what is perhaps the world’s highest-profile artificial intelligence company.

Senator Richard Blumenthal, left, and Sam Altman, chief executive of OpenAI, at a hearing on artificial intelligence in May. Mr. Blumenthal and Senator Josh Hawley, Republican of Missouri, plan to announce a sweeping framework to regulate A.I.