The Senate Foreign Relations Committee began its hearings Monday on John Bolton's nomination to be US Ambassador to the United Nations.

On Monday, Bolton in his one day of scheduled testimony rigorously rejected assertions by hard-charging Democrats that he tried to sack State Department intelligence officials who challenged his assessment of Cuba as trying to develop biological weapons and his appraisal of the weapons programs of Iran and other countries.

"I didn't seek to have these people fired. I didn't seek to have them discharged. I said I lost my trust in them," Bolton testified.

Bolton also assured the committee that he supports international law and views the United Nations as "an important component of our diplomacy." The 56-year-old State Department chief of arms control is a hard-liner with a skeptical view of some U.S. arms control treaties and a frequent critic of the value of the United Nations.