The commander of U.S. and NATO forces in Afghanistan is apologizing for a coalition airstrike that Afghan officials say killed 18 civilians in the country's east.

U.S. General John Allen flew to Logar province on Friday to personally offer his regrets and condolences to families of those killed in Wednesday's airstrike. It was NATO's first public acknowledgement that civilians, including women and children, were killed in the operation.

The coalition initially said “multiple insurgents” were killed in the operation targeting a Taliban leader in the Baraki Barak district. But video of the scene showed bodies of women and children.

Afghan President Hamid Karzai condemned the incident and said any airstrike that kills civilians or damages their property is neither justified or acceptable.

Wednesday's airstrike is the latest in a series of incidents in which international forces have been blamed for Afghan civilian casualties. Last week, President Karzai ordered a probe into a coalition airstrike that Afghan officials say killed eight members of a family in Paktia province.

In April, U.S. and Afghan officials signed an agreement putting Afghans in charge of special operations, including controversial night raids on Afghan homes that have been a major source of contention between the two sides.

Elsewhere in Afghanistan, authorities say at least 20 prisoners, including Taliban fighters, escaped from a jail in the northern province of Sar-e-Pul during an insurgent attack late Thursday.

Officials say insurgents set off a bomb outside the prison in the provincial capital , sparking a gunbattle with prison guards. At least three inmates were killed by guards and 28 wounded.

Authorities say many of the inmates who escaped through the rubble were recaptured and a search was on for the remaining prisoners.

The Taliban claimed responsibility for the attack.