The euro climbed against the US dollar as investors watched the Ukraine crisis ahead of a Crimea referendum vote this weekend on whether to leave Ukraine and join Russia.
The euro bought $US1.3906 around 2200 GMT (0900 AEDT), up from $US1.3867 late on Thursday.
The Japanese currency, considered a safe haven in times of uncertainty, rose against both the euro and the dollar. The euro slid to 140.73 yen from 141.15 yen, while the US dollar dropped to 101.36 yen from 101.78 yen.
"In a certain way, the euro is seen as a safe haven by a number of investors in Eastern Europe, who want to limit their risk exposure to what's happening around Ukraine, and repatriate their investments into euros," said Charles St-Arnaud, a Nomura analyst.
Tensions were rising ahead of Sunday's secession vote in Ukraine's Crimea region, with long talks between US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov failing to defuse the crisis.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The US and European allies are preparing sanctions against Russia over the issue, which could begin with visa bans on senior Russian officials, according to media reports.
"If Crimea votes to secede from Ukraine, the initial fear about the consequences including a possible Russian invasion could send currencies and equities sharply lower in early Asian and European trade," said Kathy Lien of BK Asset Management.
She predicted a strong relief rally if the majority of voters oppose joining Russia.
"Unfortunately the more likely outcome is the one that means uncertainty to financial markets. By unanimously approving the referendum, the leaders of Crimea have shown their cards and their preference for ceding control to Moscow."
The British pound rose to $US1.6650 from $US1.6620 late on Thursday.
The US dollar fell to 0.8726 Swiss franc from 0.8745 franc.
