President Samia Suluhu Hassan says she will not tolerate such "brutal acts".
Dozens were wounded in the attack which a doctors' union is blaming on the paramilitary RSF.
The vehicle was involved in a collision with a lorry carrying people and livestock.
PM Abiy Ahmed says anyone planning an attack should "think 10 times", touting Ethiopia's defensive abilities.
The UN says that "harrowing" human rights violations have been committed during the civil war.
Three children are injured days after 21 children died in a fire at another Kenyan school.
More than 100 inmates died trying to flee Makala Prison - the latest disaster to hit the overcrowded jail.
More than 100 inmates died trying to flee Makala Prison - the latest disaster to hit the overcrowded jail.
More than 100 inmates died trying to flee Makala Prison - the latest disaster to hit the overcrowded jail.
Ugandan Olympic runner Rebecca Cheptegei died after her former partner allegedly set her on fire.