Power arrived in Mali Monday, becoming the first sitting U.S. Cabinet-level official to visit the country in more than a decade.
Mali has worked since a coup in 2012 to restore a sense of national security and territorial integrity. It's since held democratic elections, but last year called for military support from former colonial power France to help fight al-Qaida rebels who seized northern territory in the wake of the coup.
"The violence that split your country took many lives and left a multitude of scars that have not yet had time to heal," Power told Malian leaders.
U.S. Secretary of State John Kerry in November said Mali had taken an important step forward with its post-conflict recovery through legislative elections, but the U.N. Security Council said threats may be re-emerging.
Jordan, serving as the rotating head of the U.N. Security Council, issued a three-page presidential statement last week saying terrorist groups were making a comeback.
"We do not want to see history repeat itself," Power said. "This is the moment to build a new, brighter future for all the Malian people."