The Japanese yen weakened past 159 per dollar on Tuesday as the dollar drew modest safe-haven demand after a US plan to cut Iran off from the global financial system underscored the greenback's central role in international trade. Dollar gains were limited by renewed concerns about a potential US debt crisis and skepticism over the effectiveness of the US Treasury Department's expanded debt buyback plan. Seiji Adachi, a former Bank of Japan board member, said the central bank will likely raise rates next month and again as early as January, warning that keeping rates unchanged could trigger another yen selloff and accelerate import-driven inflation. Markets are pricing in about an 80% probability of a 25-basis-point rate increase to 1.25% next month, sharply above the roughly 23% probability priced in before the Bank of Japan's July meeting.