Thousands of people have demonstrated in Sanaa to demand both the removal of Shia Houthi fighters who control the Yemeni capital as well as the country's president.
The demonstrations on Saturday were the first of their kind demanding President Abd-Rabbu Mansour Hadi step down since he took over the presidency after a popular revolt toppled his predecessor, Ali Abdullah Saleh, in 2011.
Many in the streets chanted slogans accusing Hadi of mismanaging the country to the point where state institutions collapsed and fighters could take over.
The demonstrators, from a variety of political groups, also denounced Wednesday's attack on a police academy in Sanaa that killed 38 people, calling for a swift investigation and trial of the culprits.
They have named their protest the Rejection movement and similar protests took place in the central city of Ibb and in Taez, Yemen's third-largest city.
Yemen's main security body has blamed al-Qaeda for the police-academy attack and security forces have arrested five suspects.
Al-Qaeda in the Arabian Peninsula (AQAP), one of al-Qaeda's most active wings, has staged a growing number of bombings and shootings across the country.
However, an AQAP leader has denied the group was involved.
"Al-Qaeda has nothing to do with the incident," Sheikh Saleh Abdel Ilah al-Dahab said on Twitter, accusing the Houthi fighters of being behind the bombing.
Security in Yemen has diminished since the 2011 popular uprising that led to a change of government and splits in the army.