WASHINGTON — A former North Carolina senator, John Edwards, is calling for the Bush administration to take immediate action to stop the killings in Darfur and Uganda, casting the humanitarian crisis in Africa as an opportunity for America to exert its moral leadership.

Mr. Edwards, who is running third in most national polls in the race for the Democratic presidential nomination, made the call yesterday at a town hall meeting in North Carolina and in remarks to a Jewish group in Washington.

“Here is a place where America can demonstrate that we are willing to take action that does not appear to be in our short-term strategic interests,” Mr. Edwards told several dozen members of the National Jewish Democratic Council. The 2004 vice presidential nominee has called repeatedly and insistently for a withdrawal of American troops from Iraq, but he sought yesterday to emphasize that he was not advocating an isolationist foreign policy.

“America has to stay engaged with the rest of the world,” he said.

Among other steps, he said America should immediately enforce sanctions against the Sudanese government and provide logistical support to U.N. and African peacekeeping troops in the region.

Speaking to a Jewish group, Mr. Edwards appeared to depart from prepared remarks focusing on the situation in Sudan to address his stance on Iran and its nuclear ambitions. He said policy-makers should seek to exploit what he said was President Ahmadinejad’s “politically vulnerable position” in Iran. “We need to drive a wedge between him and his own people,” Mr. Edwards said. Regarding military action against Iran, he said a president could never take any options off the table, but he focused on pressuring Iranian leaders through diplomacy and the threat of economic sanctions.

The other Democratic candidates, including Senators Obama and Clinton, are scheduled to address the same group today and tomorrow.