[JURIST] Pentagon officials admitted Tuesday that US troops in Iraq used white phosphorus [CDC factsheet; GlobalSecurity.org backgrounder] as an incendiary weapon against enemy combatants during a 2004 military assault on the insurgent-controlled city of Fallujah, but remained adamant that it was not used against civilians. Reports that US forces fired white phosphorus rounds into the city, causing severe burns, were circulated at the time [SF Chronicle report], and rights organizations expressed repeated concerns over alleged violations of international humanitarian law [JURIST report] during the siege. The US, however, denied the allegations [USINFO report] and said that white phosphorus shells "were fired into the air to illuminate enemy positions at night, not at enemy fighters." Officials now admit they used white phosphorus as a psychological weapon against insurgents in trench lines. An Italian television station aired a documentary earlier this month alleging that chemical weapons were used against civilians [JURIST report], but military officials denied the allegations [JURIST report]. Pentagon officials also say that white phosphorus is not banned by any international weapons convention the US has signed. AP news has more.