Opponents of Yemen's Houthi militia announced the formation of a national alliance on Saturday to restore the authority of the state, in a major shakeup of Yemen's political landscape.

Shi'ite Muslim Houthis invaded Yemen's capital, Sanaa, in September and dissolved parliament last month. That created a political vacuum which is threatening to push the towards a civil war.

The coalition, called the National Salvation Alliance, formally unites players from across Yemen's regional and ideological divides. It may strengthen their hand in ongoing United Nations-backed talks for a unity government.

"Its goal is to protect the state from collapse and disintegration while seeking to build a federal, democratic Yemen which rejects militias no matter whose side they may be on," Manea al-Matari, a former protest organizer and a member of the bloc, told Reuters.

The seven parties include activists, Islamists and members of Yemen's former ruling party, who back President Abd-Rabbu Mansour Hadi from his base in the country's South.

It replaces the Joint Meetings Party, an opposition umbrella group founded in 2005. It joined many of the same groups that opposed Hadi's predecessor, veteran autocrat Ali Abdullah Saleh, until he was swept from power by Arab Spring protests in 2011.

There was no immediate comment from the Houthis or from U.N. mediator Jamal Benomar during an interview with pan-Arab channel Al Jazeera aired on Saturday.

"The ball is in the court of the political factions and parties. They have to be more serious this time, because the situation is very dangerous," Benomar said.