The dollar gave up further ground against the yen in Tokyo on Friday amid reports that U.S. President Bill Clinton supports a stronger yen.The dollar plunged to 115.70 yen at one point, its lowest level in 14 months in Tokyo, before settling at 117.18-22 yen at 5 p.m., down from 122.35-37 yen late Thursday.The greenback has plunged nearly 9 percent in two days, its steepest slide since the world's industrial nations switched to the floating exchange rate system in 1973 to let their currencies' values be determined by market forces of supply and demand.Speaking to reporters at the White House, Clinton said "the strengthening of the yen could be a good thing," according to reports from Washington. The media reports quoted Clinton as saying the yen's appreciation in recent days would be a balancing of forces in the world economy.Japanese bank officials sounded a skeptical note about Clinton's reported remarks, saying they cannot be taken as indicating a major shift in U.S. policy. A weak dollar is posing a serious threat to the thus far robust U.S. economy and can come back to haunt the world economies, said Mamoru Shimode, a strategist with Deutsche Morgan Grenfell Capital Markets Ltd.Finance Minister Kiichi Miyazawa meanwhile told reporters that Japanese monetary authorities do not need to step in to help bolster the dollar. Miyazawa stuck to his laissez-faire policy on the currency market, apparently fearing that efforts to keep the dollar afloat artificially will undermine the long-term process of keeping exchange rates stabilized.He added that he believes currency rates will stabilize in due course. "It is not necessary" to intervene in the foreign exchange markets, Miyazawa told a regular news conference in the morning, adding, "You never know about the future, though."