A US drone strike has hit a convoy heading to a wedding party in Yemen, killing at least 13 people, officials said.
The attack took place in the Yemeni city of Radda, the capital of Bayda province. The city is known as a stronghold of al Qaida militants.
Yemeni officials said the convoy was heading to a wedding in the village of Qaifa when it was hit by the drone, and that the strike left charred bodies in the road and vehicles on fire.
One official said that al Qaida militants are suspected to have been travelling with the wedding convoy.
The US considers Yemen's al Qaida branch to be among the most active in the world.
A military official said initial information indicated the drone mistook the wedding party for an al Qaida convoy. He said tribesmen known to the villagers were among the dead.
While the US acknowledges its drone programme in Yemen, it does not usually talk about individual strikes.
If further investigations determine that the victims were all civilians, the attack could fuel an outburst of anger against the United States and the government in Sanaa among a Yemeni public already opposed to the drone strikes.
Civilian deaths have bred resentments on a local level, sometimes undermining US efforts to turn the public against the militants. The backlash in Yemen is still not as large as in Pakistan, where there is heavy pressure on the government to force limits on strikes - but public calls for a halt to strikes are starting to emerge.
In October, two UN human rights investigators called for more transparency from the United States and other countries about their drone programmes, saying their secrecy is the biggest obstacle to determining the civilian toll of such strikes.
The missile attacks in Yemen are part of a joint US-Yemeni campaign against al-Qaida in the Arabian Peninsula, which Washington has called the most dangerous branch of the global terrorist network.
The drone strike is the second since a massive car bombing and coordinated assault on Yemen's military headquarters killed 56 people, including foreigners. Al Qaida claimed responsibility for the attack, saying it was retaliation for US drone strikes that have killed dozens of the group's leaders.
Security forces in the Yemeni capital boosted their presence today, setting up checkpoints across the city and sealing off the road to the president's residence, in response to what the Interior Ministry called threats of "terrorist plots" targeting vital institutions and government buildings.
Meanwhile, in the Yemen's restive northern, ultraconservative Sunni Muslim militants and rebels belonging to a branch of Shiite Islam battled each other with artillery and machine guns in clashes that killed more than 40 people, security officials said.
The violence between Islamic Salafi fighters and Hawthi rebels has raged for weeks in Yemen's northern province of Saada, but the latest sectarian clashes marked an expansion of the fighting to the neighbouring province of Hagga. The government brokered a ceasefire last month to try to end the violence, but both sides have repeatedly broken the truce.