President condemns Nato airstrike
Ten campaign workers have been killed in a Nato airstrike in Afghanistan, the country's president Hamid Karzai said.
Nato said the attack targeted insurgents and it was investigating.
President Karzai, who has warned civilian casualties undermine anti-insurgency efforts, issued a statement condemning the attack, saying 10 campaign workers had been killed and two injured.
Nato said the attack in the north-eastern province of Takhar's Rustaq district was believed to have killed or wounded at least 12 insurgents, including two commanders.
The alliance said it was aware of Karzai's claims and was opening an investigation to discover the truth.
Meanwhile, two American troops died in fighting in Afghanistan while officials said coalition and Afghan forces had killed at least 37 insurgents in a series of ground and air engagements.
Earlier, US Defence Secretary Robert Gates arrived in the capital Kabul for meetings with President Karzai and top Nato commander General David Petraeus.
Mr Gates flew to Kabul from Baghdad, where he participated in ceremonies marking the formal close of the US combat mission in Iraq.
The Pentagon chief also plans to visit US troops in Afghanistan.