The yen has seen the biggest advance among major currencies after the US conducted a missile strike on Syria.
The Japanese currency, traditionally viewed as a safe haven, was up 0.4 per cent at ¥110.38 per dollar around lunchtime in Tokyo.
Shortly after reports of the strike broke across news wires, the yen strengthened as much as 0.6 per cent to ¥110.13, just a whisker away from hitting its lowest intraday level since mid-November.
The Swiss franc, also seen as a haven in times of crisis, was flat at $1.0048, but had rallied by as much as 0.2 per cent against the dollar.
The dollar index, a measure of the US currency against a basket of global peers, was flat at 100.66. The index of the world’s reserve currency initially gained as much as 0.1 per cent following news of the strike, but started to pare gains as the yen (part of the index’s basket) rallied.
Overall, currency markets were pulling back from their initial burst.
The Mexican peso was the worst performer among major currencies, down 0.4 per cent, followed by a 0.2 per cent drop for the Australian dollar and also the South Korean won.