A roadside bomb in Yemen's capital Sanaa killed three soldiers and injured two others while they were on a security patrol, a security official said.
The official said the blast early on Saturday targeted a car in Sanaa's al-Hasaba district, a centre of opposition to former Yemeni leader Ali Abdullah Saleh who was ousted early last year.
The official, who requested anonymity, said it was unknown who carried out the attack.
The deadly blast came after a period of relative calm in the Yemeni capital.
Yemen's politicians are currently taking part in a national dialogue aimed at paving the way for a new constitution and planned February 2014 general elections.
The impoverished Arabian Peninsula country has been hit by violence attributed to Al-Qaeda fighters, southern armed groups and a Shia rebellion in the north.