The Islamic State group claimed an attack on two Houthi rebel leaders in Sanaa on Monday night that medics said had killed at least 28 people, including eight women.
The car bomb attack targeted Houthi rebel chief brothers Faycal and Hamid Jayache during a gathering to mourn the death of a family member, a security source said.
Houthi rebels closed down the surrounding area in the centre of the city after the attack, only allowing through emergency services to help evacuate the victims, witnesses said.
In a statement posted online, the Islamic State group said it had organised the attack on what it called a "Shia nest" in the Yemeni capital.
The extremist Sunni jihadist group considers Shia as heretics and has frequently targeted them in attacks in several countries.
The last of these, a suicide bombing by a Saudi national on Friday in a Shia mosque in Kuwait, killed 26 people and wounded 227 others.
IS has also claimed a car bombing on June 20 against a Shia mosque in Sanaa that killed two and wounded 16 and another series of attacks in the Yemeni capital four days earlier that killed 31.
The jihadist group, which marked the first anniversary of the declaration of its "caliphate" in Iraq and Syria on Monday, has been ramping up deadly attacks in Yemen since March.
Iran-backed Houthi rebels have seized vast swathes of Yemen since launching an offensive in July 2014, forcing President Abedrabbo Mansour Hadi to flee the country.
Neither peace talks in Geneva or a Saudi-led air campaign begun in March have driven them from power and they remain locked in battle with pro-government fighters, Sunni tribesmen and southern separatists.