KABUL: The US commander of Nato forces in Afghanistan has apologised over the deaths of civilians in an air strike this week, flying personally to the scene to deliver his condolences.

President Hamid Karzai had expressed outrage over the incident, in which Afghan officials said 18 civilians including women and children were killed, and cut short a visit to Beijing to return home.

Nato commander General John Allen flew to Logar province south of Kabul “to see local leaders and the population to apologise and offer condolences to the families”, spokesman Brigadier General Carsten Jacobson told AFP.

This was the first public acknowledgement by Nato that civilians died in the air strike on a home in the province in the early hours of Wednesday.

Nato's International Security Assistance Force (Isaf) says multiple insurgents were killed in the strike, which was ordered after troops came under fire during an operation against a Taliban insurgent leader.

“We did a call out of those who were shooting from the building to come out, but they refused and then things escalated, culminating in the use of close air support,” an Isaf spokesman, Col Gary Kolb, told AFP.

An AFP correspondent at the scene shortly after the attack saw and filmed the bodies of five women and seven children, one as young as a year old.

“Attacks by Nato that cause life and property losses to civilians under no circumstances could be justified and are not acceptable,” Karzai said of the attack.

This is the second time within a month that Allen has had to admit civilian deaths in Nato air strikes that have strained relations between Karzai and the US, which leads international forces in the fight against Taliban insurgents.

In early May, Karzai carpeted Allen and US ambassador Ryan Crocker in the presidential palace after a number of civilians were killed in two air strikes.

Nato and US forces admitted in a joint statement after the meeting that civilians had died in two separate hits and pledged to take action to minimise any similar casualties.

The statement gave no details of how many civilians died in each of the two incidents but local officials put the total at more than 20, including women and children.

And on May 27, Karzai ordered an investigation after Afghan officials said a Nato air strike killed a family of eight, including six children, in eastern Afghanistan. The results of the investigation have not yet been released. The United Nations mission in Afghanistan also condemned the Logar strike, saying that “aerial operations have resulted in more civilian deaths and injuries than any other tactic used by pro-government forces since the present armed conflict began”.

“The incident in Logar on 6 June reinforces this trend,” it added.

For the past five years the number of civilians killed in the war has risen steadily, reaching a record of 3,021 in 2011 — with the vast majority caused by insurgents, the United Nations says.

The recent air strikes resulting in civilian deaths come after a series of incidents this year that have complicated relations between Nato forces and their Afghan allies.

They include pictures of US soldiers abusing Taliban corpses, the accidental burning of Korans at a Nato base and the alleged massacre of 16 civilians by a rogue US soldier.