He made the comments on Sunday after a one-day visit to Kirkuk and Baghdad. The day trip was part of a whistle-stop tour taking in four countries including Afghanistan.
Rumsfeld told reporters that the Pentagon was eager to recruit Iraqis to handle a variety of security duties to combat insurgents and criminals in Iraq.
Rumsfeld admitted some security staff would not receive adequate training because of the immediate need to have a visible police presence in towns and cities.
"Experts say it should take eight weeks to train a policeman. We put some out on the street after four, with the understanding that we needed them on the street and life isn't perfect."
US forces and allies are training Iraqi police, border patrol agents, civil defence corps members, site-protection guards and soldiers in a new national army. Rumsfeld admitted that at least 107 Iraqi security staff had been killed whilst doing their job in the past few months.
Iraqi police stations are prime
targets of resistance attacks
As part of a policy known in some quarters as "Iraqification," the US has trained about 145,000 Iraqis to serve in security forces. The Pentagon has planned to train a further 220,000 next year, but this number may increase.
Rumsfeld told reporters that the US government might have to ask congress to dig deeper into federal reserves to raise funds for the training.
"I'm concerned that we might not have the option of increasing if, in fact, that proves to be necessary," he said, adding that he would like to accelerate the training further.
"We feel an obligation to move as rapidly as possible to have these security forces trained and equipped and deployed so that they can assume a greater portion of the responsibility," Rumsfeld said.