The euro weakened on Monday after German Chancellor Angela Merkel's conservatives were routed in elections in a key state, while world shares eased back from their recent rally.
Concerns also lingered about reports of soaring radiation levels at a damaged nuclear plant in Japan, and about the impact of the fighting in oil-producer Libya.
Merkel's conservatives lost power in regional stronghold Baden-Wuerttemberg on Sunday, with early poll results showing the Greens, buoyed by Japan's nuclear crisis, surging to their first state premiership.
Barclays Capital said in a note that the result meant Merkel, the leader of Europe's largest economy, would be more reliant on support from opposition parties and that it could feed uncertainty about political support for a euro zone bailout package.
The euro eased against the dollar as a result, to $1.4060
but the dollar was also aided by hawkish comments from some Federal Reserve officials.
It is a combination of setbacks to German Chancellor Angela Merkel's party and the U.S. dollar being lifted by those comments from the Fed officials which led some investors to short the euro, said Adam Myers, senior currency strategist at Credit Agricole.
St. Louis Federal Reserve President James Bullard said on Saturday that lengthening the extended period of low interest rates could encourage a liquidity trap.
It followed comments on Friday from Philadelphia Federal Reserve Bank President Charles Plosser, who said the Fed would have to reverse its easy money policy in the not-too-distant future to avoid sowing the seeds of inflation.
World shares as measured by MSCI were down around 0.3 percent with the pan-European FTSEurofirst down 0.2 percent and Japan's Nikkei off 0.6 percent.
The slip followed a fairly strong rally last week that belied the overall negative news from disaster-hit Japan and turmoil in the Arab world.
We had a nice bounce last week. Markets have been resilient in the face of some hideous news, said Justin Urquhart Stewart, director at Seven Investment Management.
The Western-led military intervention in Libya was allowing rebel forces to gain ground. Syria deployed its army to the country's main port over the weekend in an attempt to rein in spreading protests across the country, while in Yemen talks stalled between the government and opposition.
Despite this, the price of crude fell. Brent was down 60 cents at $114.91 a barrel.
On bond markets, German government bonds opened lower after the election result.
Portuguese bonds meanwhile were set to remain under pressure with the country in political limbo and facing snap elections which could make it difficult for Lisbon to finance itself ahead of bond redemptions in April and June.
(Additional reporting by Brian Gorman; Editing by Hugh Lawson)