Yemen's Houthi rebels have begun a "historic" meeting with just one party after leaders of the southern separatist movement pulled out of discussions to form a presidential council to end the country's political crisis.

Only former President Ali Abdullah Saleh's General People's Congress party joined the three-day talks aimed at filling the power vacuum left after Yemeni President Abd-Rabbu Mansour Hadi and his cabinet resigned on January 22.

The first day of the meeting on Friday in Sanaa, the capital, was heavily secured by the Houthis, whom Saleh is accused of backing.

The Houthis seized control of the city in September and placed the president under house arrest, triggering his resignation and creating a vacuum of authority.

Hundreds of protesters rallied in the southern city of Aden to reject the solution offer of Houthi leader Abdel-Malek al-Houthi that includes forming a transitional presidential council formed of six members.

Three members would represent the north of Yemen and the other three would be from the south.

Al Jazeera's Jamal Elshayyal, reporting from Aden, said the southern movement pulled out of the talks because they saw the event as an "uneven playing field".

"They believe the Houthi movement ... is in control and so long as they hold the president and other figures under house arrest ... there's no point in these negotiations," Elshayyal said. 

Elsewhere in the country, witnesses said Houthis violently dispersed and detained demonstrators during nationwide rallies attended by tens of thousands, denouncing the rebel group with the slogan: "Revolt until the overthrow of the coup."

Radwan Masoud, the head of a students' union at the universities of Sanaa and Amran, was reportedly among the detained.

Sanaa University has been the focal point of anti-Houthi protests, frequently dispersed by the rebels firing in the air and detaining activists.

Elshayyal said the street protests are significant because previous demonstrations against the Houthi takeover had previously been suppressed. 

"The fact that protests are taking place could be a sign that the fear barrier has been broken," he said. "This could be a card that the southerners can play: using popular power - not military [power] - for future negotiations."

'Out Benomar'

Jamal Benomar, the United Nations envoy to Yemen, had been working with political parties on a possible power-sharing deal.

However, on Thursday a faction of the separatist Southern Movement announced that it would stop participating in the "pointless" talks "which will lead the country into the unknown".

The movement said the talks were taking place "under intimidation and a siege of legitimate authorities".

In the central Baida province, protesters accused the UN envoy of failing to end Yemen's crisis. "Out, out Benomar," they chanted against the diplomat.

The crisis has raised fears that Yemen could become a failed stated.

Source: Agencies