TOKYO (AFX-ASIA) - The dollar was sharply higher against the yen in midafternoon trade, reaching the 118.30 level, following intervention by Japanese authorities, dealers said. A dealer at a local bank said today's intervention by the Ministry of Finance was "a surprise." "Previously, they intervened at around the 117.00 level. But today, they decided to intervene at around the 117.70 level. It was a big surprise," the dealer said. "There are lots of dollar-sell offers against the yen at around the 118.30 level. It seems to me that the Japanese authorities tried to break this level through their intervention today," he said. However, he said it is still uncertain what Japanese authorities are trying to achieve through the series of interventions. "It is still uncertain what Japanese authorities are trying to achieve. But I don't think they are seriously trying to cause the dollar to rise against the yen," he said, adding he expects the aim of the intervention is to indirectly support the US treasury market. "Japanese authorities can buy US treasuries with the dollars bought from the series of interventions. I think Japanese authorities are simply moving to support the US treasury market" following the Sept 11 terrorist attacks, he said. The dealer said he expects the dollar to range between 116.50-120.00 yen in the short-term, adding that the dollar's gains are likely to be short-lived. "I think the effect of these interventions will quickly fade, possibly within one month, as an improvement in fundamentals is necessary for currencies to rise in the long-term," the dealer said. The dealer added that an expected 25 basis point rate cut by the Federal Reserve next Tuesday will not support a strengthening of the dollar, adding, "It is possible that the dollar will encounter selling pressure."