There are reports of many casualties in a car bombing outside a presidential palace in southern Yemen on the day that the country swore in a new president.
Health officials told news agencies that at least 25 people were killed and 30 injured in the attack in Mukalla, the capital of the southeastern Hadramaut province. All of those killed were soldiers in the Yemeni Republican Guard, which serves as the presidential security force.
"A pick-up truck driven by a suicide bomber exploded at the entrance of the presidential palace in Mukalla," an official said.
Reuters news agency reports that al-Qaeda has claimed responsibility for the bombing, "in retaliation for the Republican Guard's crimes".
The attack came hours after Abd-Rabbu Mansour Hadi was sworn in as Yemen's new president after being declared the winner of last week's single candidate vote, completing a transition of power that formally ended Ali Abdullah Saleh's decades-long rule.
Hadi, who served as vice president under Saleh, took the oath of office at a ceremony in Sanaa on Saturday attended by his predecessor, who returned to the country from the US for the occasion.
Yemen has been rocked by months of deadly unrest since protests against Saleh's rule began early last year.