At least 25 people, among them 15 children, have been killed in twin car bomb attack in the central Yemeni province of Bayda, reports say.
The children were inside a school bus that was passing a checkpoint manned by Shia Houthi rebels in the Radaa area when the first bomb exploded.
The second one went off soon afterwards near the home of a Houthi leader.
The rebels blamed Sunni jihadist militants from al-Qaeda in the Arabian Peninsula (AQAP) for the blasts.
They have been fighting in Radaa since the Houthis overran the AQAP stronghold in October, a month after taking control of the capital, Sanaa.
It is not clear if the school bus or the Houthi checkpoint was the intended target of the first car bombing.
The Associated Press news agency quoted the Houthis as saying the victims were all girls who had attended a local primary school.
They denounced the attack as "the ugliest crime against childhood".
The defence ministry also condemned the "cowardly terrorist attack on the home of a citizen and a school bus" and held AQAP responsible.
The Houthis did not say if the 10 people killed by the second blast were members of their group or bystanders, nor whether the man whose house was targeted, Abdullah Idris, was among the casualties.
It is the second time Mr Idris' home has been targeted since October, according to Reuters news agency.
The rebel leader is also a member of the General People's Congress Party of former President Ali Abdullah Saleh, who was forced to hand over power in 2011 after a popular uprising.
Last month, a suicide bomber killed dozens of people gathered at the residence of a tribal chief in Radaa.