Adding to the disappointing economic data, U.S. share futures and the dollar tumbled on Wednesday after reports said that President Donald Trump asked then-FBI Director James Comey to end a probe into Trump's into his former national security adviser.
This has raised questions whether obstruction of justice charges could be laid against the president.
Till now, upbeat global growth has underpinned risky assets and supported the multi-year lows in measures of market volatility.
But the retreat in the dollar, which has now given up all the gains it made following Trump's presidential election win in November, and a pull-back from record highs for world stocks points to investor unease about this week's headlines.
U.S. stock futures were off 0.5 percent, though they were still close to record highs.
More attractively valued European stocks slipped slightly, although the region's brighter economic outlook and better-than-expected corporate profits continue to draw investors.
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Recent U.S. data, which includes softer-than-expected retail sales and inflation, has raised concern about the strength of consumer sentiment.
Meanwhile, the euro zone economy started the year with robust growth that outstripped that of the United States and set the stage for a strong 2017.
"At the moment everyone is focusing on the political relief in Europe and the political unrest in the U.S.," ING's senior rates strategist Martin van Vliet said.
In commodity markets, safe-haven gold hit a two-week high, climbing 0.6 percent to $1,243.31. The precious metal has risen for five straight days.
Data showing an increase in U.S. crude investors hit oil prices as concerns about oversupply despite efforts by top producers Saudi Arabia and Russia to extend output cuts once again weighed.
Brent crude fell 0.3 percent to $51.53 a barrel while U.S. West Texas Intermediate (WTI) crude slipped 0.6 percent.