Former New York City Mayor Rudy Giuliani has emerged as a leading candidate to be U.S. secretary of state for President-elect Donald Trump, a source familiar with the situation said on Monday.

The source said John Bolton, who served as U.S. ambassador to the United Nations under President George W. Bush, was also under consideration to head the State Department.

Read moreFreemason Rudy Giuliani Is in the Lead to Be Freemason Trump’s Secretary of State (Fortune)