“His remarks could be a catalyst for some to lash out against our forces,” US and Nato forces commander Gen Joseph Dunford said in a leaked email.
International troops are scheduled to end combat missions in 2014.
In a nationally televised speech, President Karzai referred to two Taliban attacks on Saturday in Khost and Kabul that left 19 people dead.
He suggested both the US and Taliban were trying to convince Afghans the situation would worsen after 2014.
He said: “[The] bombings in the name of the Taliban were aimed at serving the foreigners and supporting the presence of the foreigners in Afghanistan and keeping them in Afghanistan by intimidating us.”
Reprinted From BBC News