The US military says it is stepping up security in Baghdad, after twin bombs rocked the heavily-fortified Green Zone of the Iraqi capital. Up to six people died in the attack, the first to occur in what is supposed to be the safest place in Baghdad. The blasts took place within seconds of each other – one in a cafe, the other in a street lined with souvenir stalls. Supporters of Abu Musab al-Zarqawi – who the US says has links with al-Qaeda – have claimed the bombings. Full Story