Updated

A NATO helicopter gunship inadvertently killed two civilians while attacking suspected insurgents in the eastern province of Khost, NATO announced Thursday.

The attack killed a suspected Haqqani network leader and two other insurgents in Tere Zayi district on Wednesday, according to NATO.

"At the time of the strike, two civilians were walking near the moving targeted vehicle," NATO said. "They were previously unseen by coalition forces prior to the initiation of the airstrike. Unfortunately both were killed as an unintended result of the strike."

Khost provincial police chief Abdul Hakim Ishaqzai said at least one of the civilians was a child.

NATO's initial description of Wednesday's attack said a "precision airstrike" killed the Haqqani leader and two other insurgents while they were driving in a vehicle. That announcement also described how NATO troops nearly missed civilians near the site of the attack.

"Just prior to the weapon impact, an unassociated civilian vehicle and two pedestrians walking in a wadi appeared, next to the target vehicle," NATO said. A wadi is a dry riverbed.

Afghan forces determined that the occupants of the vehicle close to the targeted one were unharmed, NATO said.

Accidental deaths of civilians due to coalition military operations in Afghanistan are a major source of tensions between Afghans and NATO. U.S. Secretary of Defense Robert Gates personally apologized to Afghan President Hamid Karzai after NATO troops in a helicopter gunship misidentified nine children gathering firewood for insurgents and killed them. The killing sparked protests throughout the country and calls for the international force to cease airstrikes and night raids.

At least 2,777 civilians were killed in Afghanistan in 2010, a 15 percent increase over the prior year, according to a recent United Nations report. The insurgency was blamed for most of those deaths, and while civilian deaths attributed to NATO troops declined 21 percent in 2010, Afghan leaders say the number remains too high.

Also Thursday, Britain's defense ministry said two soldiers were killed by a roadside bomb in southern Afghanistan.

The Ministry of Defense said the soldiers had just completed an operation with the Afghan National Army and the Danish Battle Group to disrupt insurgent activity and search compounds in the Nahr-e Saraj District of Helmand province.

The soldiers were returning to their own camp when their vehicle was hit by an explosion Wednesday. Both members of the 1st Battalion Irish Guards were due to return home in six days.

The soldiers were not identified but the ministry said their families had been informed.

The deaths bring to 362 the number of British forces and civilian defense workers killed in Afghanistan since 2001.

International forces have been fighting pitched battles for control of the southern part of the country, which is a key Taliban stronghold.

The latest deaths also bring to 25 the number of coalition service members who have died in Afghanistan so far this month.

(This version CORRECTS the number of NATO service members killed so far this month to 25.)