government's efforts to bring clans and sub-clans under the "umbrella" of a national army are still "a work in progress."

Kerry's Mogadishu visit took place as the United States has been working to broaden its engagement with Somalia.

In February, U.S. President Barack Obama nominated career diplomat Katherine Dhanani to serve as the first U.S. ambassador to Somalia since 1991. If confirmed by the Senate, she would lead the U.S. Mission to Somalia, which is located in Kenya.

After returning to Kenya from Somalia, Kerry will travel to Djibouti, which hosts the U.S. military hub for the Horn of Africa region. The country has also served as a stopping point for foreigners fleeing unrest in Yemen.

From Djibouti, Kerry travels to Riyadh for talks with senior leaders on regional security.

He is expectedto wrap up his trip in Paris, where he will meet with French Foreign Minister Laurent Fabius and the foreign ministers of Gulf Cooperation Council countries, plus participate in World War II Victory Day commemorations.

Americans flee Yemen

In Tuesday's briefing, the senior State Department official said more than 500 Americans are known to have departed from Yemen and traveled to Djibouti, as well as an equal number of family members.

The official said Djibouti has been relatively lenient with its entry requirements, while other countries have imposed restrictions.