Japan intervened in currency markets Monday for the first time since August, driving the yen down sharply against the dollar and euro.

Finance Minister Jun Azumi said he gave the order to begin selling yen at mid-morning after the dollar slid to 75.32 yen, its lowest point since World War II. By mid-day the dollar was trading above 79 yen and the euro had posted similar gains.

Azumi said the intervention was unilateral and would continue until he is satisfied with the result. The government is concerned that the strong yen is hurting Japan’s vital export sector and could slow the country’s recovery from the March earthquake and tsunami.

Japan last intervened to drive down the yen on August 4, selling a record 4.5 trillion yen. However the effects were short-lived and the currency quickly resumed its climb amid concerns over the U.S. and European economies.

Azumi declined to say Monday how much the government was spending on the current intervention.