|Many Afghans have been angered by the frequent civilian deaths caused by international forces [Reuters]
Hamid Karzai, the Afghan president, has rejected a US apology for the deaths of Afghan children in a NATO air raid, saying that apologies for civilian deaths are "not sufficient".
According to a statement on Sunday, Karzai told US General David Petraeus, the overall commander of international troops in Afghanistan, that expressing regret was no longer enough.
In a meeting with Karzai, Petraeus apologised for the deaths last week of nine children in the eastern province of Kunar, saying the killings were a "great mistake" and there would be no repeat.
A statement from Karzai's office said: "President Karzai said [to Petraeus] that only regret is not sufficient and also mentioned that civilian casualties during military operations by coalition forces is the main reason for tension in relations between Afghanistan and United States.
"It is not acceptable for the Afghan people anymore. Regrets and condemnations of the incident cannot heal the wounds of the people."
Hours before Karzai's statement, hundreds of people chanting "Death to America" protested in the Afghan capital
against the recent spate of civilian deaths.
Protesters later burnt an effigy of Barack Obama, the US president.
Following the Kunar incident, Lieutenant General David Rodriguez, who directs day-to-day operations of international forces across Afghanistan, later issued a video statement of apology.
Civilian casualties caused by NATO-led forces in Afghanistan are a major source of friction between Karzai and his Western backers.
Karzai's statement was issued on a day 12 Afghans were killed and another five injured, according to an Afghan official, as a result of a roadside blast in Paktika, a province in the country's east, close to the border with Pakistan.
Two children were among the dead.
Sunday's blast hit a lorry carrying civilians, Mokhlis Afghan, a spokesman for Paktika's governor, said, adding that the vehicle was travelling between the towns of Turwa and Wazakhwa.
The Afghan interior ministry confirmed the attack but said that only 10 people were killed.
Paktika, where the blast occurred, borders Pakistan's tribal areas, which are used as safe havens by fighters opposing the US-led multinational force in Afghanistan.
Fighters regularly cross the rugged frontier to attack the international forces; the region has seen an increase in fighting, as well as a rise in casualties.