The United Nations said Thursday it is negotiating with impoverished North Korea over its aid presence, which Pyongyang alleges has been politicized and wants reduced. North Korea requested in a letter last month that the UN reduce its involvement in the isolated country, spokesman Stephane Dujarric said in a daily press conference without giving details. The letter, obtained by AFP, asked that the drawdown occur before the end of the year and comes as working-level denuclearization talks with Washington remain gridlocked.