Japan's reelected minister for fiscal and economic policy Hiroko Ota said Tuesday that Japan is closely watching to what extent the subprime market problem will impact the US economy. "The impact on the (US') real economy is not so large at this moment. But there is a possibility that the problem may lead to shrinking housing investment and continue for a long time. So we are watching very closely how much impact it will have on the real economy," Ota told reporters. The mortgage market problem may affect Japan in the form of slowing Japanese exports to the US as private consumption in the US also slows, Ota said. "Nothing can be said now about what will happen. We fully acknowledged that it is a risk factor," she said.