GDANSK/TOKYO - World stocks fell to their lowest levels in almost four weeks on Friday, while the dollar hovered near multi-week highs, as the prospect of higher US tariffs sent jitters through markets and revived concerns about an escalating global trade war.

Technology shares took an additional hit following a sharp sell-off in AI darling Nvidia and other so-called "Magnificent Seven" Wall Street mega-cap stocks, as investors judged the chipmaker's earnings report harshly a day after its release.

US President Donald Trump said on Thursday that 25 percent duties on imports from Canada and Mexico will come into effect on March 4 - not April 2 as he had suggested a day earlier - and said goods from China will be subject to an additional 10 percent duty. This week he also floated 25 percent tariffs on shipments from the European Union.

"A market that had reduced its sensitivity to recent tariff headlines has had to reconsider that reaction function," said Chris Weston, head of research at Pepperstone.

"The skew for risk in the near term suggests the downside has further to go here."

Tariff fears sent risk-sensitive currencies such as the Australian dollar sliding, while the US dollar was set for its best week since late January.

Bitcoin dipped below $80,000 for the first time in more than three months, following a towering rally late last year on optimism that the Trump administration would boost the asset class.

Europe's STOXX 600 was down 0.6 percent, after the index fell about 0.5 percent on Thursday. The sub-index of technology stocks slid 1.4 percent.

The pan-European index was roughly flat on the week, after rising for nine consecutive weeks.

World stocks were on track for their worst week since mid-December, slumping more than 2 percent. On Friday, the index fell to its lowest in almost a month.

US stock futures, however, were broadly higher, suggesting Wall Street shares should recover some ground after a selloff the previous day.

A broadly firmer dollar weighed on commodities including gold.

Eyes on PCE

While the threat of escalating tariffs has spurred dollar strength, it has also stoked worries about its impact on the US economy.

Recent US data has been soft, and traders have reacted by pricing in at least two quarter-point Federal Reserve interest rate cuts this year, with the first as early as July.

Investors will keep a close watch on the Fed's preferred inflation gauge - the PCE price index - set for release later in the day. Monthly non-farm payrolls figures are due a week from now.

In Asia, Japan's Nikkei tumbled 2.8 percent, buckling under the weight of a stronger safe-haven yen.

The dollar index - which gauges the greenback against six major peers including the euro, yen and franc - touched 107.45 for the first time since February 13.

The euro languished around its lowest since February 13, after the single currency fell 0.8 percent on Thursday. It was last trading at around $1.03.

In the eurozone, preliminary data on Friday showed that French inflation dropped below 1 percent for the first time in four years in February. German and Italian data are released later.

"With the European Central Bank meeting coming next week, it's interesting to see the inflation numbers," said Jan von Gerich, chief analyst at Nordea.

"The market usually moves more to these numbers from the big countries than the final euro area number that we get next week."

Bitcoin last changed hands 6.3 percent weaker at $78,984, hovering around its lowest since November 10.

Gold sagged 0.6 percent to $2,856 per ounce, the lowest since February 10.