Japan is prepared to respond on all fronts to speculative moves in the foreign exchange market, the nation’s top currency official signaled, after authorities were suspected of having conducted intervention over the holiday period.

“We’re targeting all angles” when it comes to intervention, Atsushi Mimura, vice finance minister for international affairs, told reporters on Thursday when asked whether recent yen moves were driven by crude oil futures. He added that authorities are monitoring markets with a sense of urgency amid continuing speculative moves.

Mimura said there’s no need for him to comment on the yen’s sharp move Wednesday, when it surged about 1.8% in roughly 30 minutes to as high as ¥155.04 per dollar, the strongest level in 10 weeks. The yen was trading around ¥156.35 Thursday morning in Tokyo.