Kabul, Afghanistan (CNN) -- An Afghan civilian was accidentally killed in a coalition airstrike and three others died in a bombing staged by militants, NATO's International Security Assistance Force said on Wednesday.
Both incidents occurred in two neighboring provinces in southern Afghanistan, where fighting between coalition forces and militants has raged for years.
The killing of civilians during NATO-led operations and by militants has enraged Afghans, and the coalition has been working over the years to avoid such casualties.
NATO's International Security Assistance Force said it is probing a Tuesday air support mission in Marja, in Helmand province, that led to the death of a civilian and the wounding of two children.
The aircraft was providing backup to Afghan and coalition forces that came under fire during a patrol in Marja in Helmand province.
"We are here to protect the Afghan people and initial indications are that in this case we may have failed," said Brig. Gen. Tim Zadalis, an ISAF spokesman said.
In Kandahar province on Wednesday, three Afghan civilians were killed and nine others, including two children and a police officer, were seriously wounded, by a vehicle bombing.
The incident occurred in the province's Kandahar district.
"These events demonstrate the insurgents complete disregard for the lives of innocent Afghan civilians. This IED attack is a further reminder of the indiscriminate weapons insurgents use," ISAF spokesman U.S. Army Lt. Col. Patrick Hynes said.