Houthi rebels brought Yemen closer to civil war on Sunday, launching an offensive on the southern city of Taiz, The Wall Street Journal reports. Militants seized the international airport, key government buildings, and surrounded the residence of the city's governor.

A senior security official in Taiz told The New York Times that the Houthis were flying troops and military equipment into the airport. According to the Journal:

The Houthis' push in Taiz puts them within easy striking distance of the southern port city of Aden, where their enemy, Yemeni President Abed Rabbo Mansour Hadi, is based, raising the specter of an increasingly violent confrontation.

Protestors took to the streets upon the Houthis arrival. "Houthi militants in military uniforms fired at us directly," Sami Al Ghobari, an anti-Houthi demonstrator, told the Journal. "They seek bloodshed, since they want to enter Taiz by force, a province they are unwanted in."

The Times reports that forces loyal to Yemen's former president, Ali Abdullah Saleh, aided the Houthis in their assault on the country's third-largest city.

The State Department confirmed on Saturday that the United States has evacuated its remaining personnel from the country.

"It's hard to see how to pull back at this point," April Longley Alley, a Yemen researcher for the International Crisis Group, told the Times. "Yemen is really bracing for a nasty, protracted battle on multiple fronts."

Image via AP. Contact the author of this post: brendan.oconnor@gawker.com.