The attack sparked angry demonstrations by the people of al Bayda. The families of the victims and ‘hundreds of armed gunmen‘ demanded an explanation from the government. They ‘closed main roads and vowed to retaliate’. It is unclear what if any local response will be to the latest strike. But the people of Radaa are reportedly outraged.

Civilian casualties have been credibly reported by multiple sources in four air strikes this year, including in three attacks since President Obama made a major policy speech in May outlining rules governing drone strikes. He said: ‘Before any strike is taken, there must be near-certainty that no civilians will be killed or injured – the highest standard we can set.’

Human Rights Watch researcher Letta Tayler said that if the reports of the recent strike are true and US drones have caused multiple civilian casualties then ‘at the very least the United States owes the Yemeni people and the world an explanation of what went wrong.’

Tayler authored a highly detailed investigation into US drone strikes in Yemen in October. This  report for Human Rights Watch called for greater transparency from the US government. She told the Bureau she found the lack of official comment from Washington on the latest strike ‘shocking in light of the fact that the US only a week or two ago apologised for a strike that killed one civilian in Afghanistan.’

She added: ’Why does the US follow different rules for the conventional battlefield and what it describes as the non-conventional battlefields of Yemen and Pakistan?’

In November, it emerged that the CIA had secretly briefed Congress about the death of a child in a strike in Yemen carried out weeks after Obama’s May speech.

There have been at least 29 air strikes reported in Yemen this year. Only one other attack has had casualties in double figures: 12 people were reported killed in a possible drone strike on November 26.

US drones and jets, as well as Yemeni aircraft frequently hit targets in southern Yemen. It is often difficult to ascertain whether a particular attack was from a drone or a manned aircraft. The Bureau has recorded 55 or more confirmed US drone strikes in Yemen since 2002. These attacks have killed at least 269 people. Bureau estimates show at least 12 confirmed strikes by US conventional aircraft as well as cruise missiles have killed at least 144 people in the same period.

The Yemen Air Force is ‘barely functional‘, cannot operate at night and lacks sufficient equipment and training to defend its own airspace. President Abd Rabbo Mansur al Hadi subsequently admitted as much in a speech in Washington in November 2012.

The US has not officially commented on the attack. However, an unnamed official told Reuters: ’We have no information that corroborates these reports.’

© 2013 Bureau of Investigative Journalism