Persistent doubts about Russia's economy sent currency traders to the safety of the dollar Friday, pushing the U.S. currency up strongly against the German mark and the Japanese yen.

The dollar jumped more than a yen despite intervention threats by an influential Japanese finance official. The dollar rose 1 1/2 pfennigs against the German mark.In late New York trading, the dollar was quoted at 146.35 yen, up from 145.16 late Thursday. It also was trading at 1.8014 marks, up from 1.7855 marks.

Traders perked up when the vice finance minister for international affairs, Eisuke Sakakibara - also known as Mr. Yen because of his ability to move markets - said the flagging yen was ready to strengthen.

Unexpectedly, he also said the government was ready to intervene should the dollar rise to 147 yen. The dollar was worth about 145 yen when he spoke and rose as high as 146.45 before the trading day was over.

"The dollar has made quite a robust recovery in spite of the comments by Sakakibara," said Jim Collins, a financial futures analyst at Salomon Smith Barney in Chicago; normally traders would have run from an intervention target. "It almost gave people per-mis-sion."

The dollar also was aided by Hong Kong's intervention in its equity markets. Just one day after hitting a five-year low, Hong Kong stocks soared 8.5 percent. The government's buying spree boosted other Asian markets.

Traders dumped the mark and bought dollars as worries persisted about Russia's economy. The ruble remained under pressure and the mark fell even though Russian stocks soared Friday, registering a 15 percent rise after tumbling all week.