Although the US joined the 188 other member nations of the Nuclear Nonproliferation Treaty on Friday in giving a green light to a conference in 2012 "on the establishment of a Middle East zone free of nuclear weapons and all other weapons of mass destruction," senior US officials appeared to backtrack afterward, setting several conditions for the talks to go ahead.

Taking the toughest line, US National Security Adviser Gen. James Jones said in a statement Friday night that the United States has "serious reservations" about the 2012 conference and believes Mideast peace and full compliance by all countries in the region to their arms control and nonproliferation obligations "are essential precursors." The compliance demand appeared to be aimed at Iran, which the US believes is pursuing a nuclear weapons program despite Tehran's claims its only goal is nuclear power.

Jones also strongly defended longtime US ally Israel, which was singled out for not being a member of the NPT.