Washington — The United States has agreed to help France airlift troops and equipment into Mali, where Islamist extremists control the north.

One U.S. official said the Air Force could start cargo flights, likely using C-17 aircraft but possibly also larger C-5s, in as little as a day. But details have yet to be worked out and no timetable has been decided.

The US government had already agreed to bolster intelligence sharing to assist the French, including information from surveillance drones and spy satellites, officials said.

Hillary Clinton, the US secretary of state, confirmed the move to put intelligence resources and transport planes at the disposal of French troops.