The Afghan Cabinet says at least 33 civilians are dead as the result of NATO airstrike in southern Afghanistan _ an incident that is inflaming already heightened sensitivities over noncombatant casualties in the war.

In a statement released on Monday, the Afghanistan Council of Ministers strongly condemned the airstrike, saying it was "unjustifiable."

The Cabinet says initial reports indicate that NATO fired Sunday on a convoy of three vehicles killing at least 33 civilians, including four women and one child. The ministers say 12 others were injured while they were on their way to Kandahar.

NATO has confirmed that its planes fired on what it believed was a group of insurgents in southern Uruzgan province, but later discovered that women and children were hurt.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

KABUL (AP) _ A NATO airstrike in southern Afganistan killed at least 21 civilians, the Afghan Interior Ministry said Monday, in an incident that could inflame already heightened sensitivities over noncombatant casualties.

NATO forces confirmed in a statement that its planes fired Sunday on what it believed was a group of insurgents in southern Uruzgan province on their way to attack a joint NATO-Afghan patrol, but later discovered that women and children were hurt. The injured were transported to medical facilities.

The Afghan government and NATO have launched an investigation.

Interior Ministry spokesman Zemeri Bashary said the Sunday morning airstrike hit three minibuses traveling on a major road near Uruzgan's border with central Day Kundi province. There were 42 people in the vehicles, all civilians, Bashary said.

The NATO statement did not say how many people died or whether all the occupants of the vehicles were civilians.

Afghan investigators on the ground have collected 21 bodies and two people are missing. Fourteen others were wounded, he said.

"We are extremely saddened by the tragic loss of innocent lives," NATO commander Gen. Stanley McChrystal said in the statement. "I have made it clear to our forces that we are here to protect the Afghan people and inadvertently killing or injuring civilians undermines their trust and confidence in our mission. We will redouble our effort to regain that trust."

McChrystal apologized to President Hamid Karzai for the incident on Sunday, NATO said.

On Saturday, Karzai had admonished NATO troops for not doing enough to protect civilian lives. During a speech to the opening session of the Afghan parliament, Karzai had called for extra caution on the part of NATO, which is currently conducting a massive offensive on the southern Taliban stronghold of Marjah in neighboring Helmand province.

"We need to reach the point where there are no civilian casualties," Karzai had said. "Our effort and our criticism will continue until we reach that goal."

NATO has gone to great lengths in recent months to reduce civilian casualties _ primarily through reducing airstrikes and tightening rules of engagement _ as part of a new strategy to focus on protecting the Afghan people to win their loyalty over from the Taliban.

This is the largest joint NATO-Afghan operation since the Taliban regime was ousted from power in 2001. It's also the first major ground operation since President Barack Obama ordered 30,000 reinforcements to Afghanistan.

But mistakes have continued. In the ongoing offensive against Marjah, two NATO rockets killed 12 people in one home and others have gotten caught in the crossfire. At least 16 civilians have been killed so far during the offensive, NATO has said, though human rights groups claim the number is at least 19.

Last Thursday, an airstrike in northern Kunduz province missed targeted insurgents and killed seven policemen.

Gen. David Petraeus, who oversees the wars in Afghanistan and Iraq, said on NBC's "Meet The Press" that Marjah was the opening salvo in a campaign to turn back the Taliban that could last 12 to 18 months.

But the continued toll of civilian lives will only make it harder for NATO in its goal to win over the support of local Afghans against Taliban militants in the south.

The newly appointed civilian chief for Marjah arrived Monday to begin the task of restoring government authority after years of Taliban rule even though NATO troops are still battling insurgents in the area.

District leader Abdul Zahir Aryan will be flying into Marjah for the first time since the massive NATO offensive began Feb. 13. He plans to meet with community leaders and townspeople about security, health care and reconstruction, he said in a phone interview Sunday.

"The Marines have told us that the situation is better. It's OK. It's good," Aryan said. "I'm not scared because it is my home. I have come to serve the people."

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Khan reported from Kandahar, Afghanistan. Associated Press writers Heidi Vogt and Tini Tran contributed to this report in Kabul.