Story highlights Taliban claims responsibility for attack that killed at least 8 people in Ghazni

4 killed when car laden with explosives rams a military convoy in Helmand province

Civilian deaths in Afghanistan have surged due to improvised explosive devices, U.N. says

Gunmen shot a convoy of fuel trucks, killing 6 drivers in Farah province on Tuesday

At least 12 people were killed and dozens were injured Wednesday in separate attacks in Afghanistan, including an insurgent assault near a post for coalition and Afghan forces, local authorities said.

In the eastern Afghan city of Ghazni, insurgents killed at least six civilians and two Afghan troops -- and injured 57 other people -- in an attack near a Provincial Reconstruction Team compound Wednesday afternoon, the provincial governor, Mosa Khan Akbarzada, said.

The Taliban claims responsibility for the attack, Taliban spokesman Zabihullah Mujahid said.

The assault began when a suicide bomber detonated his car near the PRT compound, according to Akbarzada. Then six attackers opened fire on Afghan troops, he said.

Most of the casualties were women and children, according to Akbarzada.

The NATO-led International Security Assistance Force confirmed the attack involved a a suicide vehicle bomb, indirect fire and small arms fire. It declined to say whether its personnel were injured.

Earlier Wednesday, in a suicide car bomber killed four people and injured 15 more in southern Afghanistan's Helmand province, a government official said.

The attacker rammed his car, laden with explosives, into a military convoy in Lashkargah, Helmand province spokesman Omar Zwak said.

He believes the bomber was targeting foreign soldiers, but all who died were civilians, he said.

CNN is seeking comment from the ISAF on possible coalition casualties. There has been no claim of responsibility for the Helmand attack.

Roadside blasts in Helmand province, which is in southern Afghanistan, killed eight people earlier this month.

Wednesday's attacks came a day after Taliban fighters opened fire on coalition fuel trucks in southwest Afghanistan, killing six drivers and injuring 10 other people, according to a local official.

At least 40 of the ISAF vehicles burned in the attack in Farah province, said provincial government spokesman Abdullrahman Zhwandai.

The Taliban claimed responsibility for the Farah attack.

Civilian casualties in Afghanistan increased 23% in the first six months of this year, the United Nations said in a report released at the end of July.