Houthi fighters in Yemen have used live ammunition to break up demonstrations against their takeover of the capital city Sanaa, witnesses have said.

The Houthis fired live rounds in the air to break-up a rally in Sanaa on Saturday, as tens of thousands demonstrated in several cities denouncing the takeover of much of the capital by the Shia movement.

Rallies took place in the central provinces of Ibb and Taiz, while in the central Bayda province, protesters blamed the United Nations envoy to Yemen, Jamal Benomar, for failing to end the country's crisis.

The Houthis, who have long been concentrated in the northern highlands where Shia Muslims form a majority, have captured several key cities across the north as they push to control more territory of the country.

Saturday's demonstrations came as efforts to resolve the country's political crisis appeared to be crumbling after the separatist 'Southern Movement' suspended its participation in talks to form a new government.

The group, which demands a return to the full independence of the southern region enjoyed from 1967 to 1990, dubbed the talks an "absurd dialogue" and "a waste of time".

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. 

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 was heavily secured by the Houthis, whom Saleh is accused of backing.

In other developments, at least three people were killed and five others wounded in clashes between the army and gunmen from the Southern Movement in Lahj province.

Source: Al Jazeera