The yen weakened on Monday, pushing the dollar to its highest against the Japanese currency since June 1990, with markets alert to any signs of intervention from the Japanese authorities to prop up the yen.
The decline in the yen comes amid a broadly stronger dollar underpinned by economic data that has pushed out the expected timing of the first Fed rate cut to September from June and escalating tensions in the Middle East.
The dollar extended gains on Monday after stronger-than-expected March retail sales data.
The yen's slide against the dollar has revived anticipation of currency intervention. Japanese Finance Minister Shunichi Suzuki said he was watching currency moves closely, and that Tokyo is "fully prepared" to act.
The dollar was last up 0.66% at 154.28 yen, its strongest since 1990.
