Militants in Yemen Seize State Offices, Force Premier to Resign

The militants known as Houthis have been protesting outside government ministries in the capital San'a since August, complaining about rising fuel prices and demanding the government quicken the pace of political overhauls. By Sunday evening, they had taken over the central bank and the defense, interior and finance ministries, adding to advances last week that included the airport.

Shortly after Sunday's takeover, the Houthis, President Abed Rabbo Mansour al Hadi and most of the country's major parties signed a United Nations-mediated cease-fire that included an agreement to form a new government. Mr. Hadi will choose the next prime minister but must consult with the parties that signed the agreement, details of which were scarce. The Houthis are likely to have an edge in those negotiations after their recent display of force.

Prime Minister Mohammed Salem Basindwa's departure may further the sectarian chasm in Yemen, as he was supported by the Islah party, a Muslim Brotherhood offshoot popular among the country's Sunnis. Islah supporters and the Houthis have clashed in recent weeks.

Signaling that the Houthis may respect the position of Mr. Hadi—a U.S. ally—and U.S. counterterrorism interests in the country, the militants occupied every major government building on Sunday except for the presidential palace and the headquarters of Yemen's special-operations forces, which are trained by their American counterparts.

"We respect President Hadi and have never demanded that he is changed. Yemeni factions are unified under his leadership and we join their lines and support him," said Zakaria al Shami, a senior Houthi leader.

Although Houthi leaders haven't demanded President Hadi's ouster, the group's increased hold over the government will likely draw rancor from Saudi Arabia, a neighbor that has financially supported Yemen for years. The Saudis accuse the Houthis of being a proxy for Iran, the kingdom's archenemy and have engaged with the group militarily, when it has advanced on the long, porous border the countries share. The Houthis deny that allegation.

There was no immediate Saudi government response about the takeover of the capital. But the Saudis could cut aid to Yemen, as they did to Lebanon in 2008, when the Shiite militant and political group Hezbollah received greater powers in that country's parliament.

"This corrupt Yemeni government is over. They worked for the interests of the West and ignored the interests of the people," said Ali Yahya, a member of the Houthi committee organizing protests in San'a.

Mr. Yahya left his job in August and said protesters wouldn't move their tents from near San'a International Airport until the government's ouster.

After the deal was signed on Sunday, Yemenis likened the atmosphere in San'a to a hostage situation, as hundreds of armed Houthi militants patrolled the city, the army and police nowhere to be seen.

Any clawing back of financial aid to Yemen could further social unrest, with poverty affecting more than 54% of Yemenis. The country has one of the world's highest population-growth rates, according to the World Bank. In addition to the turmoil of the Houthi rebellion, Yemen also faces secessionist calls from the south and an al Qaeda insurgency that has continued to make gains across the country, including San'a.

Mr. Hadi is a chief regional counterterrorism ally for the U.S., which runs a secretive drone program in the country against al Qaeda in the Arabian Peninsula with the president's permission.

The U.S. considers AQAP al Qaeda's most deadly branch in terms of a global threat. The U.S. gave $350 million to Yemen last year, evenly split between civilian and military aid, said American officials. That was up from $28 million in 2008, before the U.S. resumed its drone program after an eight-year hiatus.

Before the 2011 uprisings that forced President Ali Abdullah Saleh out after a two-decade autocratic rule, the Houthis' power was contained to Saada, a province north of the capital.

There was no immediate comment from the State Department on Sunday's events. But the U.S. did condemn Houthi protests in the capital in late August and the group's takeover of Amran province just north of San'a and the looting of weapons from a military compound there, saying such moves undermined the political process.

Houthi fighters saw limited resistance from security forces on Sunday, particularly the police, who were ordered not to clash with the group after it became clear that they were going to overtake the capital and levy their demands on the government. By about 3 p.m. Sunday, clashes between security forces and the Houthis ended after the militants took over major military positions in the capital, an interior ministry official said.

"The Houthis will very soon be part of the Yemeni government, so starting today we need to accept that and not revert to bloodshed," the official added.