KABUL (Reuters) - Afghanistan's Taliban on Sunday accused the United Nations of "enmity and political motives" in reporting that three-quarters of a record-high number of civilians killed and wounded this year were victims of the insurgents.

Denouncing a U.N. report as "biased and unfounded", the insurgents accused U.N. investigators of intentionally skewing statistics to blame the Taliban.

The United Nations said that for a second year, insurgents were responsible for about 75 percent of civilians killed, with the toll reaching a new high of 3,188 through November, more than for any other full year since it began tracking numbers.

The Taliban said in a statement emailed to journalists the assertion was false.

"Civilian casualties in the current war are mainly caused by the heavy blind U.S. air bombardments," the militants said, citing disputed reports that a U.S. air strike killed several school children last week.

They also asserted that Afghan army, police and militias indiscriminately kill civilians and slammed the United Nations for classifying government officials who were assassinated as civilians - the Taliban consider all Afghan government workers legitimate targets.

The United Nations called on Friday on all sides of the war to work to limit civilian deaths and injuries.

(Editing by Robert Birsel)