Japanese authorities moved quickly Thursday to dispel widespread concerns about the yen's recent sharp rise against other major currencies, with the prime minister, Cabinet members and Bank of Japan officials trying to calm markets and talk up the unit's value.

But despite market expectations that they may offer responses to address the problem, their announcements fell short of dispelling uncertainty over the future course of the currency, which advanced to its highest level against the dollar in 15 years on Wednesday.

Prime Minister Naoto Kan expressed concern Thursday about the yen's summer ascent against the dollar and other major currencies, describing the trend as "too rapid."

Kan raised the issue with Chief Cabinet Secretary Yoshito Sengoku, a senior government official said.

By midday in Tokyo, the dollar traded at around ¥85, slightly recovering after falling to ¥84.72, its lowest level since July 1995, at one point in London on Wednesday.