RIYADH (Reuters) - A Saudi-led Arab coalition on Saturday conceded that an air raid in Yemen’s capital a day earlier had resulted in civilian casualties, blaming the incident on an unspecified “technical error”.

People search under the rubble of a house destroyed by a Saudi-led air strike in Sanaa, Yemen August 25, 2017. REUTERS/Khaled Abdullah

The early morning attack in the Faj Attan area of Sanaa hit a vacant building but caused an adjacent apartment block to collapse, killing at least 12 people, six of them children, residents have said.

Coalition spokesman Colonel Turki al-Maliki defended the strike as having “a legitimate military target”, which he said was a Houthi command and control center. He accused the fighters of using civilians as human shields.

“A technical error was the reason for the unintentional accident and the house in question was not directly targeted,” he said a statement carried by Saudi state news agency SPA.

Maliki said the coalition expressed remorse for “collateral damage to civilians” but did not specify the extent of casualties.

However, a senior ICRC official visited the site of the strike on Friday and said, “From what we saw on the ground, there was no apparent military target.”

Yemen’s long war involving competing Yemeni factions and regional power struggles has killed at least 10,000 people. Millions more have been forced to leave their homes and face disease and hunger.

The Houthis and their ally, former president Ali Abdullah Saleh, control much of the north of the country, including Sanaa. Yemen’s internationally recognised government is backed by the Saudi-led military coalition and is based in the south.

The United States and Britain provide arms and logistical assistance to the alliance for its campaign. The issue has caused controversy in Britain over the toll on civilians.

As well as military targets, air strikes have hit hospitals and ports, exacerbating the humanitarian crisis.