The Army acknowledged Monday that it had killed a television journalist after soldiers mistook his camera for a rocket-propelled grenade launcher. Press advocacy groups called for an investigation. Meanwhile, efforts to rebuild Iraq were set back over the weekend with explosions on the country's lifeblood oil pipelines and the capital's water supply. The water main in Baghdad was bombed Sunday as two fires raged out of control along an oil pipeline to Turkey, halting exports just days after they started. The army said the first fire was started by someone who ignited oil leaking from a burst pipe, but might not have been sabotage - backing off earlier claims that it was intentional.