A review of the United States' nuclear arsenal due to be released on Monday has been delayed again.<br /><br />Barack Obama, the US president, had planned a sharp reduction in the arsenal as part of a new strategy to be outlined in the Nuclear Posture Review.<br /><br />White House officials say the finished document will call for more reliance on using conventional weapons as a deterrent.<br /><br />The review is also supposed to get rid of a programme to develop a nuclear weapon that can detonate underground.<br /><br />Al Jazeera's Patty Culhane looks at what Obama promised exactly. (Mar 2, 2010)