The UN says civilian deaths in Afghanistan rose 40 percent in 2008 to a record 2,118. An annual UN report says militants were responsible for 55 percent of civilian deaths last year, or 1,160. But the world body says US, NATO or Afghan troops killed 829 - 39 percent of the total. The remaining 130 deaths couldn't be accounted for because of issues like cross-fire. Civilian deaths have been a huge source of friction between the US and President Hamid Karzai, who has increased demands that US and NATO troops avoid killing civilians during operations. The UN report released Tuesday says the number of civilians killed by US, NATO or Afghan forces rose 31 percent from 2007 to 2008. In 2007 those forces killed 629 civilians.