A car containing explosives blew up while trying to attack a presidential palace in southern Yemen, killing at least 26 people and injuring several others, according to witnesses and medics.
The attack, apparently by a suicide bomber, happened in Hadramout, far from the capital of Sanaa, where Yemen's new president took an oath of office.
Yemen's south is a turbulent region where secessionists are seeking to revive a socialist southern state and where an active wing of al Qaeda has taken root.
No group has yet claimed responsibility for the attack.
Meanwhile, a Yemeni soldier died in hospital after being shot during clashes as troops moved in to dismantle a tent camp of southern militants in the port city of Aden, medics said.
Three other people, including a woman, were wounded in the exchanges.
Gunfire broke out when army units attacked the camp, in Martyrs' Square in the city's Mansura quarter.
They met stiff resistance from the southerners, who have been camped out in the square for months, and the fighting lasted for several hours before the troops managed to break up the camp.
Hospitals reported receiving four wounded - two soldiers and two civilians. One of the soldiers later died.
Aden is a stronghold of militants demanding either autonomy or outright independence for the south, which was a separate country until 1990.
Southern activists seriously disrupted a single-candidate election on Tuesday that annointed Vice President Abdrabuh Mansur Hadi as the country's new leader, the first new president in Sanaa since 1978.
Hadi was sworn in today, ending the rule of Ali Abdullah Saleh, who agreed to step down under a Gulf-brokered deal signed in November after months of deadly unrest.
