From The Washington Post:

Shiite insurgents overran Yemen’s presidential palace and shelled the president’s nearby residence Tuesday in an escalating offensive striking at the heart of the Western-allied government. The coup-style strikes by the Houthi rebel faction — believed backed by Iran — posed the most serious challenge yet to President Abed Rabbo Mansour Hadi, a staunch ally of the United States in the fight against al-Qaeda’s powerful branch in Yemen.