The Iran nuclear deal must be changed if the United States is to remain in it, the top U.S. diplomat said on Tuesday, suggesting its key limits on the Iranian nuclear program must be extended.

Making his debut appearance at the annual United Nations General Assembly, U.S. President Donald Trump accused Iran of exporting "violence, bloodshed and chaos" and of seeking to project its influence in Yemen, Syria and elsewhere in a region rife with sectarian conflicts between Sunni and Shiite Muslims.

"We cannot let a murderous regime continue these destabilizing activities while building dangerous missiles, and we cannot abide by an agreement if it provides cover for the eventual construction of a nuclear program," Trump said.