Houthi insurgents leading a crusade against the Yemeni government attacked and captured the presidential palace and residence in Sanaa on Tuesday, with president Abed Rabbo Mansour Hadi believed to be holed up in his home. The Zaydi Shiite group has said they do not intend to overthrow Hadi; to see their demands met, however, "all necessary measures will be open."

Hadi has been a major ally to the United States in the fight against al Qaeda, namely by allowing drone strikes on targets in the region. American officials worry that a fractured Yemen would leave the country vulnerable to nearby terrorist groups—al Qaeda in the Arabian Peninsula, the group who claimed responsibility for the Charlie Hebdo massacre, is based in Yemen. The Houthis have been vocal about their opposition to Yemen's collaboration with the U.S., accusing leaders of corruption.

"What happened was that they [the political leadership] have sunk deep into corruption and tyranny," leader Abdel Malik al-Houthi said in a televised address Tuesday. "The nation has started moving towards a tragic situation and complete collapse. The situation has worsened on all fronts— political, economic and security—on a large scale."

A major sticking point in the Houthis' demands include the removal of a provision in a constitutional draft that proposes the splitting of Yemen into a six-region federation; the group kidnapped Ahmed Awad bin Mubarak, Hadi's chief of staff, Saturday, "in an apparent move to extract [those] changes," Agence France-Presse reports.

The Houthis' seizing of the presidential palace is being received as a major setback for the Yemeni government and a crucial turning point in Houthi campaign. From the New York Times:

The Houthi advance on Tuesday, and its leader's ultimatum, cemented the group's status as Yemen's most powerful opposition movement. And Mr. Hadi, the steward of an internationally backed political transition plan, appeared more sidelined than ever. The Houthis' rise began in September, when Houthi fighters swept into Sana, seizing control of crucial government installations and vowing to force Mr. Hadi's government to carry out political and economic reforms. The Houthi movement — which began as an activist group seeking greater rights for Yemen's Zaydi Shiite minority and fought six wars against the central government — has consolidated its control in the capital and beyond.

In battles Monday between Houthis and the Yemeni government, the Washington Post reports, nine people were killed; the country's prime minister, Khaled Bahah, has reportedly been contained to another palace by the rebels.

[Image via AP]