NATO forces in Afghanistan expressed regret on Wednesday for civilian casualties that may have been caused by operations carried out against suspected insurgents.

A total of 22 Afghan civilians were reportedly killed in operations in two Afghan provinces on Wednesday.

Asadullah Khalid, a provincial governor, said nine civilians were killed and 11 wounded in Zhari district of Kandahar province when NATO air strikes hit three houses.

Meanwhile, Abdul Rehman, a resident, said 13 civilians including women and children were killed in Grishk district of Helmand province after a rocket hit one house. Three Afghan police officers were also wounded.

Rehman, who spoke with relatives of the dead in the village of Tajikai in Helmand province, said a rocket launched from an aircraft landed on a home and killed everyone inside the house.

"The government and NATO are fighting the Taliban, and civilians are the victims," Rehman said.

Tajikai, with a population of about 100 families, is a farming village about 220 kilometres west of Kandahar city.

The International Security Assistance Force, a NATO-led international force of about 30,000 troops in Afghanistan, said in a news release that it makes every effort to minimize the risk of "collateral damage" when it conducts its operations.

ISAF said it "deeply regrets causing any civilian casualties" in its operation in Kandahar province,  but it did not say whether the casualties included deaths, injuries or both.

"Close air support was used in support of the operation, and it is believed that the air attack caused several civilian casualties along with an unknown number of insurgent casualties," it said.

"The operation's purpose was to detain individuals involved in the recent improvised explosive device attacks in Panjwaii."

Brig.-Gen. David Fraser, commander of the ISAF regional command in southern Afghanistan, spoke to the provincial governor about the operation and the governor has talked directly to some of the victims, according to the release.

Canada has more than 2,000 troops in Afghanistan, with the majority stationed in southern Afghanistan, primarily in Kandahar.

With files from the Associated Press