Clashes between Sunni Salafis and Zaidi Houthis escalated as more than 14 fighters from both sides were killed in the fighting over the last 48 hours.
Eyewitnesses on the ground said though Houthis were having the upper hand in the fighting, Salafi militants succeeded in taking over checkpoints and military positions previously under the control of the Houthis.
At least three Houthis and four Salafis were killed on Thursday.
Mediation committees were formed between both sides to help end the conflict. However, no success has resulted though hundreds of tribal and political leaders have tried to help in ending the crisis.
Salafis claim that the Houthis are supporting a Shia mission to expand in Yemen.
Zaidism is an Islamic sect with close links to the Shia sect of Islam.
More than 85 people have been killed over the last month in the secratian violence in Sa’ada, north Yemen.
The Houthi movement now controls Sa’ada after six long wars with the government since 2004.
Houthis rejected the latest GCC power transfer proposal and called it a catastrophe that will never be forgiven by the Yemeni people.