The French-led military intervention in Mali could take years, a U.S. official warned on Monday.

A State Department official for Africa said the U.S. would like to see an African-led, -owned and -directed operation like the one that successfully pushed militants out of Somalia's capital after several years of warfare. But Don Yamamoto warned that intervention could take years before finding success.

"This is only the first phase. It is going to take time. I think people should not be into the illusion that it is going to be quick," said Yamamoto, the principal deputy assistant secretary of state for African affairs.