Kabul , Afghanistan ( CNN ) -- Two Americans and three Afghan soldiers died in a firefight that might have involved insurgent forces , the International Security Assistance Force said Sunday . One of the U.S. deaths was a soldier ; the other was a civilian , U.S. officials said . The coalition first said the clash Saturday was the latest in a spate of insider attacks involving Afghan forces , which have killed more than 50 NATO troops this year . Later , the coalition called that into question . It appears the clash in Sydabad district might have been provoked by insurgent fire , said Lt. Gen. Adrian Bradshaw , the ISAF deputy commander , at a news conference . Marine killed in Afghanistan predicted insider attack that lead to his death . The firefight took place at a temporary checkpoint being operated by ISAF troops in Wardak province , west of Kabul . An Afghan National Army , or ANA unit , was nearby , Bradshaw said . `` According to ISAF and ANA reporting , after a short conversation took place between ANA and ISAF personnel , firing occurred which resulted in the fatal wounding of an ISAF soldier and the death of his civilian colleague . '' Neither the statement nor Bradshaw indicated who fired the fatal rounds . Investigators from ISAF and the Afghan army were trying to establish `` whether the initial exchange of fire was provoked by insurgent firing , '' Bradshaw said . `` That is not clear , '' but `` there is a report of insurgent fire , '' he said . In its statement , ISAF called the clash `` tragic . '' The incident brings the confirmed U.S. death toll inside Afghanistan to 2,002 , according to a CNN account . The deaths include four U.S. civilians . The thoughts and prayers of the president and first lady `` go out to the families of those who sacrifice so much for this country in Afghanistan , including the families of those who have made the ultimate sacrifice , '' said Josh Earnest , a spokesman for President Barack Obama . Insider attacks by Afghan soldiers and police officers -- or militants wearing uniforms -- have been on the rise for months . ISAF : Insurgents in deadly attack in Afghanistan wore U.S. Army uniforms . So-called `` green-on-blue '' attacks have been climbing this year , triggering concerns about the stability of Afghan security forces ahead of planned NATO withdrawals in 2014 . `` Green-on-blue '' refers to a color-coding system used by the military , in which blue refers to international troops and green refers to allied Afghan forces . `` Make no mistake though that these attacks do not diminish in any way the commitment of the president , the commitment of our men and women in uniform , the commitment of our allies to follow through and complete successful transition to Afghanistan by 2014 , '' said Earnest . The senior combat leader in Afghanistan , Gen. John Allen , said he is `` mad as hell '' about the insider attacks , but he stressed it is important to remember the majority of Afghans are `` with us in this . '' `` We 're willing to sacrifice a lot for this campaign , but we 're not willing to be murdered for it , '' he said during an interview with CBS ' `` 60 Minutes '' that aired Sunday night . Afghan President Hamid Karzai also appeared on the show . He described the attacks as `` sad '' and spoke about the security situation . `` The reason for the NATO and American intervention in Afghanistan was terrorism . Terrorism has not gone away . It has increased , '' the president said . `` We must then question how come they 've returned . ... Something must have gone wrong for that to happen . '' NATO 's ISAF troops are training Afghan soldiers and police to maintain security in the country ahead of the planned end of allied combat operations . This month , U.S. troops in Afghanistan were ordered to halt joint operations with local security forces in some areas on account of such attacks . Opinion : Green-on-blue attacks show there 's no easy way out of Afghanistan . Roadside bomb kills 2 in Afghanistan . Afghan troops taking on perilous fight against insurgency . Journalist Ben Farmer and CNN 's Amir Ahmed , Michael Pearson and Josh Levs contributed to this report .
NEW : Gen. Hamid Karzai and President Hamid Karzai discuss security on ` `` 60 Minutes '' may have been provoked by insurgents , the U.S. Embassy commander says . A civilian contractor killed in the clash was Afghans , the U.S. Embassy confirms . A Afghanistan service member also died in the Saturday incident , ISAF says .