Investors are still nervous despite Wall Street's huge rally

Japan's Nikkei jumped nearly 4%, pulling the index out of the bear market it had entered just two days ago. Stocks also climbed more than 1% in Australia and Singapore.

But other markets showed investors remain nervous after weeks of turbulent trading and worries about global economic growth.

The Hang Seng in Hong Kong and the Shanghai Composite both shed more than 0.6% after weak Chinese industrial data highlighted the difficulties the world's second largest economy is facing. US stock futures were pointing lower, and European indexes were mixed at the start of their first day of trading since Monday.

The major US indexes had staged a major comeback Wednesday following their worst ever Christmas Eve. The Dow, S&P 500 and Nasdaq all leaped 5% or more. Crude oil prices, which have been beaten down in recent months, also spiked amid the rush of optimism.

But market experts are still advising caution despite the dizzying rebounds in the United States and Japan.

"Such rallies are not uncommon in troubled times, and we have experienced many of them in past bear markets," said Hussein Sayed, chief market strategist at online broker FXTM.

"To call for a bottom, we need at least a couple of days of strength, not just in price, but also in trading volume, breadth of the market" and economic fundamentals, he said in emailed comments.

The sustainability of Wall Street's rebound remains "questionable" because of "concerns over economic growth next year and ... many political and economic uncertainties" such as the unresolved US-China trade war, CMC Markets analyst Margaret Yang wrote in a commentary. Similar doubts are weighing on Asian markets, she added.

Investors were given a stark reminder of China's economic slowdown on Thursday, with official data showing a year-on-year drop in industrial profits in November — the first in nearly three years.

"China economic growth in my books remains to be the most significant market risk as we enter 2019," said Stephen Innes, head of Asia-Pacific trading at online broker Oanda.

More volatility likely

Global markets had plunged earlier in the week amid unsettling signals from Washington that made traders fret about the stewardship of the world's biggest economy.

They included President Donald Trump's attacks on Federal Reserve Chairman Jerome Powell, the partial shutdown of the US government and Treasury Secretary Steven Mnuchin's unusual statement about the country's banks.

Investors shouldn't rule out more volatility in the days ahead, according to Innes.

"Don't get too comfortable, as discussions regarding the various political and policy questions remain hanging in the balance," he said.