* Yen hits five-month high versus euro
* Risk-off flows spurred by Russia sanctions
* Dip in U.S. Treasury yields hits dollar (Adds New York open, quotes; changes byline, dateline; previous LONDON)
By Michael Connor
NEW YORK, July 17 (Reuters) - The dollar was mixed on Thursday, hurt by falling Treasuries yields, while the yen was lifted to a five-month high against the euro by anxious investors repositioning after the West imposed more sanctions on Russia.
The dollar was up against both the euro and the yen, which was down 0.2 percent against the dollar at 101.51 yen . The euro weakened to as little as 137.185 yen , its lowest since early February, and last traded at 137.34 yen, off 0.1 percent for the day.
An index that measures the dollar against a basket of six other leading currencies was off 0.05 percent at 80.517 but still near a one-month high touched on Wednesday.
"The yen has been a beneficiary overnight," said Alan Ruskin, global head of foreign exchange strategy at Deutsche Bank in New York. "Some of the so-called riskier assets, riskier currencies, have tended to trade softer."
European stocks were in the red while German bunds, another safe haven in times of turmoil, were in demand as the United States slapped sanctions on some major Russian companies including its biggest oil group and largest independent natural gas producer.
The sanctions brought the Russia-Ukraine dispute back to center stage, reminding investors the crisis has the potential to disrupt global markets and an economic recovery.
"There is a worsening of risk sentiment linked to the events in Russia that is driving up the yen," said Yujiro Goto, currency analyst at Nomura.
"Also dollar/yen has been rising in the past few days, so we are seeing some unwinding of those positions. There should be good support at 101.20 for dollar/yen."
U.S. Treasury yields, which are a key attraction for dollar buyers, fell on Thursday, with the yield on the benchmark 10-year note dropping to 2.499 percent.
U.S. economic data, showing jobless claims diminishing and housing starts tumbling 9.3 percent, helped lift Treasuries' prices.
"The bond market was rallying before the data, and (the data) has given a little bit more substance to the ... rally," Ruskin said.
(Reporting by Michael Connor; Additional reporting by Anirban Nag in London and Hideyuki Sano in Tokyo; Editing by James Dalgleish)