A UN Security Council delegation on Sunday began a brief visit to Yemen in a clear boost to President Abdrabuh Mansur Hadi aimed at helping to iron out problems hampering national reconciliation talks.

Thousands, meanwhile, took to the streets on the occasion of the visit, demanding an end to the immunity given to former president Ali Abdullah Saleh who was eased out of office in February 2102 after three decades of rule following a UN-backed and Gulf-brokered deal.

The Security Council delegation, which includes the head and members of the top body, held talks with Hadi, state television said, adding that the team later went on to meet members of the government.

It termed the visit as "international support for Yemen to push political reconciliation as per the Gulf initiative" which ended Saleh's rule and nearly a year of bloodshed.

The trip comes as Sanaa struggles to organise a national dialogue conference that would result in a new constitution and presidential and parliamentary elections in February 2014, thereby ending the current two-year transition period.

The conference, originally set for mid-November, has been repeatedly delayed as some factions of the Southern Movement, which has campaigned for autonomy or secession for the formerly independent south, have refused to join the talks.

After North and South Yemen unified, in 1994, a short-lived secession bid was crushed by Sanaa troops and since then the citizens of the south have complained of discrimination.

The United Nations special envoy Jamal Benomar said the team's visit "reflects the UN Security Council's interest in pushing the reconciliation and removing obstacles that are hindering the implementation of the points of the Gulf initiative."

He told state television that the "process is difficult," and urged all Yemeni parties to "realise that there is a historic opportunity and join the national dialogue without preconditions to solve all Yemeni issues, including the question of the south."

On Sunday, demonstrators poured into the streets of Sanaa amid tight security calling to bring Saleh to justice and to "return the funds stolen by the former president and his family," a correspondent reported.

The Youth of the Revolution, a group that was the main engine of the year-long protests, also called for an international probe into violations and crimes committed by Saleh's regime.

It urged the UN Security Council to "freeze the funds owned by the leaders of the former regime and return them to public treasury."

"The people want to put the killer on trial," chanted the protesters, referring to Saleh who is also accused of hampering the political transition.

The transition deal also stipulates restructuring the army and integrating military and security forces under a single command, a task that remains difficult with Saleh's sons and relatives still occupying senior security posts.

The United Nations made an urgent call in December for Yemeni political parties to begin the dialogue, warning that the transition was under threat.