Defense Secretary Robert Gates said Sunday that U.S. troops probably would remain in Iraq for a «protracted period,» but at a reduced level and with a more limited mission, according to AP. He would not say how large a force he envisioned in the coming years. «I don't know what the numbers would be,» the Pentagon chief said in a broadcast interview. «Assuming the conditions prevail in Iraq that allows us to continue the drawdown that the president has talked about, the idea is that we would have a much more limited role in Iraq for some protracted period of time, a stabilizing force, a force that would be a fraction of the size of what we have there now,» Gates said. In the long term, Gates said, U.S. forces would focus on border security, fighting terrorists and training and equipping Iraqi security forces. Gates spoke on «This Week» on ABC.