US officials denied reports that Jordanian militant Abu Musab al-Zarqawi had been captured near the western Iraqi city of Fallujah. "We have heard those reports and we do not believe they are true," Lieutenant Colonel Steve Boylan, a US military spokesman in Baghdad said. Iraq's US-backed interim government has said it will launch a major offensive in Fallujah unless the city hands over Zarqawi and his militant followers. Some Iraqis say Washington exaggerates the threat from Zarqawi to disguise the strength of Iraq's homegrown insurgency.