SANAA ?-- About 32 people were killed in a suicide bombing in Yemen's capital on Thursday morning, police and witnesses said.

A suspected al-Qaida terrorist detonated explosives near Shiite Houthi militants who were gathering for protests in downtown Sanaa, which left about 32 people killed and dozens wounded, police and witnesses told Xinhua.

The Houthi group was expected to rally on Thursday to protest against the nomination of the newly-designated Prime Minister Ahmed Awad bin Mubarak who announced his resignation earlier in the day.

A Houthi spokesman has confirmed that 21 Houthi members were killed and dozens wounded in the explosion.

On Wednesday, Houthi leader Abdul Malik al-Houthi called for mass protests in the capital Sanaa over the appointment of Mubarak as new prime minister.

He said there was "foreign interference" when the president was considering candidates of the prime minister.

"We received assurances that this name (Ahmed Awad bin Mubarak) was eliminated but right after the meeting with the American ambassador, the name resurfaced," al-Houthi said.

On Sept. 21, the government and Shiite Houthi group signed a cease-fire deal in Sanaa, both agreeing to stop fighting in the capital, nominate a prime minister within a week and form a technocrat government within a month.

However, the Houthi group refused to hand over towns and cities seized in the previous weeks and has taken over almost all state institutions in Sanaa since then.

The deal empowers the Houthi rebels as it allows the group to play an important role in forming a cabinet and determining the future control of the army.

The peace agreement put an end to deadly clashes between the rebels and the army supported by Sunni militia, which left about 400 people killed, including about 50 civilians.

After it overran the capital, the Houthi group started to deploy fighters in the country's southern regions, where the al- Qaida in the Arabian Peninsula (AQAP) was active.

The Houthi group clashed with the AQAP several times in the central province of Marib and southeastern province of Hadramout in late September, which left dozens dead from both sides.