The United States will increase its support for the Iraqi security forces, Defense Secretary Donald Rumsfeld said Thursday, adding that it continues to be “enormously challenging” to stop the violence there. Rumsfeld said he has completed a new assessment of the progress of the Iraqi forces, and said he was not satisfied. “We intend to increase their budgets,” as well as their capabilities, and officials will work to make the improvements more quickly, Rumsfeld said. He did not provide figures. The U.S. defense chief said people should stop demanding specific timelines for progress in Iraq, saying it was too difficult to predict when Iraqis can take control of their country.