Yemen's opposition has accused outgoing president Ali Abdullah Saleh of trying to torpedo a power transfer deal by sparking a new crisis, as troops loyal to him clashed with opposition forces, killing three people.
The president's signature on a power transfer deal has not ended months of turmoil that have benefited al Qaida-linked militants. Sunday's clashes followed Saleh's decision not to leave the country, a move likely to embolden his relatives who control key security posts.
Opponents demand the removal of all Saleh's relatives from such positions. Huge crowds of protesters have called for Saleh to be put on trial for the killing of hundreds of protesters, though the power transfer deal gives him immunity from prosecution.
Vice president Abed Rabbo Mansour Hadi told his new national unity government on Sunday, in their first official session, that the power transfer agreement, engineered by Yemen's powerful Gulf Arab neighbours, must be implemented soon. "We need to move vigorously and effectively to implement the Gulf initiative and its mechanisms," he said.
The new government's first task is to push through the law shielding Saleh from prosecution for alleged corruption and violence against protesters. He made that a condition of the deal to relinquish power after 33 years of rule.
Yet more than a month after he signed, and after the possibility of his flying to the US was raised, Saleh is still in Yemen, wielding significant power and showing few signs of giving in.
Ten months of mass protests and clashes between forces loyal to Saleh and his opponents, including army units that followed powerful tribal leaders siding with the opposition, have left a power vacuum.
The Yemen branch of al Qaida, considered one of the world's most dangerous, has taken advantage of that to dig in to positions in the south, taking over towns and villages. Yemen's military fights frequent battles with the Islamist militants but has failed to dislodge them.
In the latest skirmish, anti-government tribesmen in the el-Fardha Nehem region, about 50 miles north-east of capital Sanaa, said two people were killed and two others wounded when Saleh's Republican Guards, led by his son, shelled their homes. In the capital, a civilian bystander was killed when Republican Guard troops clashed with supporters of tribal chief Sadeq al-Ahmar, who was once a regime ally but defected in March, activists said.
Opposition spokesman Mohamed Sabri accused Saleh of undercutting security as a way of arguing that he should stay in power. "This man does not respect his commitments with others," Mr Sabri said. "Saleh is creating a new crisis."