The dollar index traded around 101.5 on Tuesday, holding onto the previous session’s gains as investors awaited the Federal Reserve’s policy decision, with markets pricing in an over one-third chance of a rate hike. That marks an unusually high level of uncertainty this close to a Fed meeting compared with recent years. Citadel Securities also said it expects the Fed to raise interest rates this week to reinforce Chairman Kevin Warsh’s inflation-fighting credibility after the central bank chief repeatedly pledged to restore price stability. Meanwhile, the probability of a Fed rate hike in September currently stands at around 56%. The dollar also remained resilient even after President Donald Trump said the US was engaged in "good talks" with Iran to end the Middle East conflict, a development that pushed oil prices lower and eased concerns over inflation and tighter monetary policy.