Why the rebuilding efforts are delaying in Iraq?

The head of the US-led reconstruction of Iraq says the ongoing insurgency there is delaying rebuilding efforts.
   Rebuilding Iraq has been a costly and dangerous business, and it’s only just begun. Bill Taylor who oversees the American reconstruction efforts admitted that a lot of work still needed to be done. He conceded that the money set aside by the US was limited, that Iraq could also need foreign investment. But he acknowledged that even oil companies that are used to working in risky places are staying out of Iraq. Insurgent attacks have already killed 295 contractors working on American projects alone.