HONG KONG, March 17 : The U.S. dollar drifted on Tuesday as traders weighed developments in the Iran war, while the Australian dollar eased slightly ahead of an expected rate hike from the country's central bank later in the day. The euro was 0.12 per cent lower at $1.1492 in Asian trading, while sterling was also down 0.1 per cent at $1.33, pulling back the sharp gains from the previous session. The dollar index was little changed at 99.913. Sentiment turned jittery again after several