The United States would support two permanent seats for African states on the U.N. Security Council, Linda Thomas-Greenfield, the American ambassador to the United Nations, said on Thursday. But the path to making that promise a reality is complicated.

The announcement, which echoes a similar call from the U.N. Secretary General António Guterres to overhaul the Council so it would reflect the world powers of 21st century, comes ahead of the U.N. General Assembly later this month.

The Security Council has 15 members, five of which have permanent seats with veto power: the United States, Russia, China, Britain and France. The other 10 members of the Council rotate every two years. Adding any new permanent members would require the approval of all five permanent members and changing the U.N. charter, a dim prospect given the divisions among the permanent members.

Adding only African countries as permanent members would likely get pushback from other countries, including Japan, Brazil, India, Germany and Italy. For years, those nations have also lobbied for seats, arguing that the world had evolved since the aftermath of World War II when the world body was founded.

Still, Ms. Thomas-Greenfield’s announcement could be viewed as a geopolitical gesture toward repairing U.S. relations with Africa, which have been frayed by the conflicts in Ukraine and the Gaza Strip, and toward matching Chinese and Russian influence there. The two U.S. rivals, which have been keen on expanding their influence on the continent, have already backed permanent seats for Africa on the Security Council.

Ms. Thomas-Greenfield may also be considering her legacy at the United Nations as her term possibly draws to an end, with the American election looming in November and the likelihood that a new administration would appoint a new ambassador. During her tenure, she has made Africa a priority of her diplomacy, frequently traveling to the continent.