A Saudi-led military offensive against Houthi rebels in Yemen has scored major gains this month, including recapturing the strategic port of Aden and the country's largest air base, after the Pentagon more than doubled the number of American advisors to provide enhanced intelligence for airstrikes.
The role of about 45 U.S. advisors, up from 20, at joint military operations centers in Saudi Arabia and Bahrain has been vastly overshadowed by the far larger U.S.-led air war against Islamic State militants in Iraq and Syria. So has Yemen's toll of civilian casualties and refugees.
The turmoil has benefited Al Qaeda's powerful local franchise, which remains resilient and continues to seize territory.