An informal ceasefire in Yemen between security forces loyal to Ali Abdullah Saleh, the president, and a tribal group has brought a pause in political unrest.
However, Al Jazeera's sources said that despite the truce, explosions were heard in Sanaa, the Yemeni capital, on Saturday.
Fighting this week has killed at least 120 people, prompted thousands of residents to flee Sanaa.
The latest violence, pitting Saleh loyalist forces against members of the powerful Hashed tribe led by Sadiq al-Ahmar, was the bloodiest since pro-democracy unrest erupted in January and was sparked by Saleh's refusal to sign a power transfer deal.
In another development, three French aid workers disappeared in Yemen's southern province of Hadramout on Saturday, but it remains unclear whether they had been abducted.
Tenuous calm
Tribal sources and residents said a tenuous calm prevailed in Sanaa's northern district of Hasaba, the scene of heavy clashes this week for control of government buildings, and outside Sanaa, a city now divided between the sides.
A government official said mediated talks were planned aimed at reducing tensions and fighting had been suspended for the duration of the discussions.
The International Crisis Group, a prominent think-tank, said a broad, lasting ceasefire was needed immediately and should be part of a plan that leads to a transition of power.
"To prevent further escalation and loss of life, the most urgent step is for both sides to immediately accept a ceasefire mediated by Yemen's statesmen and tribal leaders," the ICG said in a "conflict risk alert" issued late on Friday.
Foreign states should be involved, it said, "but, given the deeply personal and tribal nature of the feud between the Salehs and al-Ahmars, it cannot be addressed effectively by international mediation or initiatives alone".
The political crisis has already cost the economy as much as $5bn and immediate aid is needed to prevent a meltdown in the country with a nominal GDP of $31bn, the country's trade minister told the Reuters news agency.
"The economy should not be held hostage to the political crisis, because the situation is alarming," Hisham Sharaf Abdalla said.
On Friday, Yemeni tribesmen said they had captured a military compound from elite troops loyal to the president 100km outside Sanaa, widening a conflict that so far has been concentrated mainly in the capital.
New conditions
The fighting has overshadowed a largely peaceful protest movement that started months ago aimed at ending Saleh's 33-year-long rule and inspired by the movements that brought down the long-standing leaders of Tunisia and Egypt.
Saleh has repeatedly imposed new conditions each time a Gulf-led transition agreement was due for signing, most recently demanding a public signing ceremony, according to mediators.
Machinegun fire and explosions rattled Sanaa this week before clashes eased after mediation efforts. Al-Ahmar's fighters evacuated government ministry buildings they had taken over in return for a ceasefire and troops withdrawing from their area.
There are worries that impoverished Yemen, where some 40 per cent of the country's 23 million people live on less than $2 a day, could become a failed state located on a shipping lane through which three million barrels of oil pass daily.
PHOTO CAPTION
A tribesman loyal to the tribal leader Sadiq al-Ahmar holds his rifle as he secures a street near al-Ahmar's house in Sanaa May 28, 2011.
Agencies