ABC News’ Matthew Jaffe reports: U.S. nuclear energy agency chief Gregory Jaczko repeated to ABC News Wednesday evening that there is “no water” in spent fuel pool number 4 at Japan's Fukushima Daiichi nuclear plant in the wake of last week’s disaster there. “I’m talking to NRC staff that we have in Japan that are working with counterparts in the Japanese utility and other officials with the regulatory bodies. They continue to believe that there is a severe concern with the spent fuel pool number 4 because it does not have a sufficient cooling and water in the pool,” Jaczko told ABC News in an interview following his appearance earlier in the day at a Congressional hearing. “My understanding is that there is no water in the spent pool,” he said. After Jaczko’s initial comments at the hearing, Japanese officials denied his claims. Asked if he was confident of the information that he was highlighting, Jaczko said he stood by his claims. “In particular we took a look at all the available information we had, and we thought that if we had that same information here in the United States, as a prudent measure, we would take or issue instructions to evacuate to a much larger area,” he told ABC. “And, like I say, I hope that the information in the end that I have is wrong because it’s been a terrible tragedy for the people in Japan and I hope that it is in fact wrong.” Jaczko, the head of the US Nuclear Regulatory Commission, declined to speculate on what might happen next. “I know efforts are ongoing to try and address the situation and deal with it,” he said.