US-led forces said that they fired by mistake on a group of vehicles that carried women and children.

The strikes took place in Uruzgan province on Sunday.

Interior Ministry Spokesman Zemeri Bashary said Monday he had reports of 33 people killed, where 42 people were in the vehicles, all of them civilians.

The Afghanistan Council of Ministers in a statement strongly condemned the air strike, saying it was "unjustifiable."

The Afghan government and the US-led forces say they have launched an investigation into the issue.

High civilian casualties - inflicted by the coalition forces - have escalated anti-occupation sentiment among Afghans and have been a source of tension between the government of Afghan President Hamid Karzai and Washington.

Local Afghan officials said that six civilians were also wounded in the attack that occurred in Dolat Khel in Kapisa province on Monday.

On his part, the angry Afghan president held up a picture of an 8-year-old girl whose entire family was killed during an offensive in the southern town of Marjah.

"If a little girl is to collect the dead bodies of family members, you can guess in what situation we are in now," Karzai said.

Many Afghan civilians have been killed both by violent militant acts, including bombings and daily fighting, as well as by US military operations in the country.