Internal United Nations maps show a marked deterioration of the security situation in Afghanistan during this year's fighting season, countering the Obama administration's optimistic assessments of military progress since the surge of additional American forces began a year ago.

The Wall Street Journal was able to view two confidential "residual risk accessibility" maps, one compiled by the U.N. at the annual fighting season's start in March 2010 and another at its tail end in October. The maps, used by U.N. personnel to gauge...