Fighting overshadowed the first meeting on Saturday of Yemen's new unity government, tasked with trying to avert civil war after a power transfer brokered by the country's Gulf neighbours.
Clashes in the southern province of Abyan killed 11 militants and two soldiers while a soldier was killed in overnight fighting in the capital Sanaa between supporters and opponents of outgoing president Ali Abdullah Saleh, officials said.
State news agency Saba said Vice President Abd-Rabbu Mansour Hadi, to whom Saleh transferred power under a deal to ease him from office, chaired the meeting of the newly sworn-in cabinet, which includes members of the opposition.
The government faces a host of challenges including sporadic fighting with anti-Saleh tribesmen, a southern separatist movement, a Shi'ite Muslim rebellion in the north and the threat from a regional wing of al Qaeda that has exploited upheaval to strengthen its foothold in the poor Arabian Peninsula country.
Top oil exporter Saudi Arabia shares U.S. fears that more instability in Yemen could embolden the country's al Qaeda wing - against which Washington has waged a campaign of drone strikes - in a country sitting next to oil shipping routes.
Hadi called on the government to help build up stability after 10 months of protests against Saleh's 33-year rule.
Everyone in Yemen expects you to focus on the main tasks of this government and steer clear of issue which give rise to discord, Saba quote Hadi as telling the new cabinet.
Hadi also headed the first meeting of a committee of officials and senior officers which will oversee the military under the transition plan, Saba said.
FIGHTING IN SOUTH, CAPITAL
In continuing clashes between government troops and al Qaeda-linked militants, 11 Islamists and two soldiers were killed on Saturday east of the city of Zinjibar, centre of Abyan, a military official told Reuters.
Late on Friday, a soldier was killed in fighting between government forces and opponents of Saleh in Sanaa, the Defence Ministry said.
The violence near government buildings and the compound of Sadeq al-Ahmar, a foe of Saleh who commands significant forces, was the latest challenge to the transition plan.
The Defence Ministry on its website accused the Ahmar tribesmen of attacking the northern neighbourhood of Hasaba with the aim of derailing efforts towards establishing security and stability in the capital and other areas.
The opposition accused troops from the Republican Guard, headed by a son of Saleh, of breaking a truce and firing artillery salvos at northern districts of the capital on Saturday, wounding at least one person.
In Oslo, Tawakul Karman, one of the three women sharing the Nobel Peace Prize, on Saturday lambasted the international community for not backing revolution in her native Yemen and said Arab despots who turn against their own people should not receive immunity.
On Friday, a Yemeni official said that forces loyal to Saleh and opposition gunmen were withdrawing from the streets of the city of Taiz, calming a situation that also threatened to wreck the power transition deal.
A committee set up to restore normality to Taiz was clearing roadblocks set up by Saleh opponents and loyalists during street battles and overseeing their withdrawal from occupied buildings, the official said. Dozens were killed in recent weeks.
Under the transfer plan, Saleh's General People's Congress and opposition parties divided up cabinet posts and formed a national unity government to steer the country towards a presidential election in February.
Yemen has also faced a fuel shortage partly due to repeated attacks on a pipeline feeding its refinery. Traders said on Friday that the country was seeking to buy four cargoes of gasoline in January via a tender amounting to 120,000 tonnes to help deal with the shortages.
(Additional reporting By Mohammed Mukhashaf in Aden; Writing by Firouz Sedarat; Editing by David Cowell)