The dollar index steadied near 99 on Tuesday after gaining some ground in the previous session, supported by safe-haven demand as the US moved to cut Iran off from the global financial system, highlighting the greenback’s central role in international trade. Treasury Secretary Scott Bessent announced plans on Monday to isolate Iran through sanctions targeting countries doing business with the Islamic Republic. Still, the dollar remained near three-month lows as the Treasury Department announced an expansion of its buyback program for long-dated government debt in an effort to contain rising borrowing costs. However, markets speculated that the plan may offer only a temporary solution, while renewing concerns over the risks of a US debt crisis and dollar weakness. Elsewhere, investors looked ahead to the latest US PCE price index data and Fed Chair Kevin Warsh’s speech at the annual Jackson Hole symposium this week for fresh clues on the monetary policy outlook.