Suicide bombers targeting Yemen's powerful Shia Houthi group and an army camp killed at least 67 people in two separate attacks.
The attacks came hours after a political crisis forced the new prime minister to step down.
At least 47 people were killed, including four children, when a suicide bomber detonated a belt packed with explosives at a Houthi checkpoint in the centre of the capital Sanaa where Houthi supporters were preparing to hold a rally.
The massive blast also wounded at least 75 people.
In eastern Yemen at least 20 soldiers were killed in a suicide car bombing and gun attack on an army outpost.
The militant group al-Qaeda in the Arabian Peninsula (AQAP) has waged repeated attacks on army installations and government facilities in eastern Yemen in recent months.
The attacks occurred just hours after a showdown between the Houthis and President Abd-Rabbu Mansour.
The row forced Prime Minister-designate Ahmed Awad bin Mubarak to step down
His appointment on Tuesday under a power-sharing deal signed last month had angered Houthi leaders.
