Investors, also facing the likelihood of a prolonged US government shutdown, fled to the relative safety of bonds and gold during the first day of a week of trading shortened by the Christmas holiday, even after Trump's Treasury secretary responded to an ongoing selloff by calling top US bankers on Sunday and making plans to convene a group of officials known as the "Plunge Protection Team."
"There are a whole number of factors that have triggered this latest risk-off climate, including the Fed's very modest deviation from its (rate increase) plan and the government shutdown in the United States," said Investec economist Philip Shaw.
MSCI's world equity index, which tracks shares in 47 countries, was 0.59 percent lower and down almost 7 percent over the past eight sessions. The index touched its lowest since early 2017.
The US Senate has been unable to break an impasse over US President Donald Trump's demand for funds for a wall on the border with Mexico, and a senior official said the shutdown could continue into January.
"We may get some clarity on several factors in early 2019 starting with a clearer line of sight on the prospect for a resolution in US-China trade dispute, but until there are some nerves flying around," said Shaw.
US stocks have fallen sharply in recent weeks on concerns over slowing economic growth and efforts by the US Federal Reserve to tighten monetary policy, with the S&P 500 index on pace for its biggest percentage decline in December since the Great Depression. The Nasdaq has fallen nearly 22 percent from its Aug. 29 high.
Trump on Monday blasted America's independent central bank saying the Fed is the country's only economic problem. It "does not have a feel for the market," he tweeted.
US stocks followed broad indexes in Europe and Asia lower on Monday morning, with markets in Germany and Italy closed and trading volumes small.
The Dow Jones Industrial Average fell 421.72 points, or 1.88 percent, to 22,023.65, the S&P 500 lost 37.78 points, or 1.56 percent, to 2,378.84 and the Nasdaq Composite dropped 50.76 points, or 0.80 percent, to 6,282.23.
"Markets (are) still under pressure from last week's more hawkish Fed update, exacerbating fears about slowing growth and more expensive refinancing following years of stimulus," said Mike van Dulken, head of research at Accendo Markets.
The political uncertainty has only added to the air of risk aversion. Benchmark 10-year Treasury notes were last 5/32 higher in price, yielding 2.7739 percent.
The gap between two and 10-year yields has shrunk to 0.14 percentage points, a flattening of the curve that has sometimes heralded coming recessions in the past.
"Many of the financial and economic indicators that turn first around business cycle peaks are now flashing red in advanced economies," warned Simon MacAdam, global economist as Capital Economics.
"This is consistent with our view that the recent loss of momentum in the world economy will develop into a more severe slowdown in 2019."
The flight to safe havens again boosted the yen, with the dollar hitting its lowest levels against the Japanese currency since August. The yen last strengthened 0.66 percent versus the greenback to 110.50 per dollar.
Gold too has regained its appeal, holding near six-month highs over $1,266 per ounce.
Oil prices were near their lowest since the third quarter of 2017, having shed 11 percent last week. US crude futures were last at $44.61 per barrel.