(Reuters) - Wall Street’s main indexes fell more than 2 percent on Friday in a broad sell-off led by declines in big Internet and technology shares, and posted their largest weekly percentage drops since March as concerns over U.S.-China trade tensions and interest rates convulsed Wall Street.

The S&P 500 erased virtually all of its gains from a week earlier, when the benchmark index notched its biggest weekly rise in seven years.

Following a weekend truce between Washington and Beijing in talks in Argentina, stocks have been volatile all week as investors comb through the news looking for signs of whether a trade-tension cloud over the stock market would dissipate.

Concerns over U.S.-China trade relations were fanned by White House trade adviser Peter Navarro’s comments that U.S. officials would raise tariff rates if the two countries could not come to an agreement during a 90-day negotiating period.

Along with trade, Wall Street has been focused on bond yields and the direction of interest rate policy from the Federal Reserve, with some investors expecting a slower pace of hikes than previously anticipated.

“It’s a crisis of confidence on the trade situation, what’s going to happen there, and maybe a little bit of a crisis of confidence in the Fed, given how quickly they have got to change their tune,” said Walter Todd, chief investment officer at Greenwood Capital Associates in Greenwood, South Carolina.

The Dow Jones Industrial Average .DJI fell 558.72 points, or 2.24 percent, to 24,388.95, the S&P 500 .SPX lost 62.87 points, or 2.33 percent, to 2,633.08 and the Nasdaq Composite .IXIC dropped 219.01 points, or 3.05 percent, to 6,969.25.

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Technology shares tumbled, with the S&P 500 tech sector down 3.5 percent. Healthcare shares .SPXHC, the biggest gainer among major S&P sectors this year, dropped 2.5 percent.

The S&P 500’s 50-day moving average fell below its 200-day moving average, a phenomenon known as a “death cross” and one that some market watchers see as a bearish near-term signal.

(Graphic: Hundreds of U.S. stocks are marking year lows - tmsnrt.rs/2RHJX9R)

For the week, the Dow fell 4.5 percent, the S&P 500 slid 4.6 percent and the Nasdaq dropped 4.9 percent.

The Dow Jones Transport Average .DJT tumbled 8 percent for the week, its biggest weekly drop in more than seven years. The small-cap Russell 2000 fell 5.6 percent, its biggest weekly drop since January 2016.

Government data showed U.S. job growth slowed in November and wages increased less than forecast, suggesting some moderation in economic activity that could support expectations of fewer interest rate increases from the Fed in 2019. The Fed is due to meet Dec. 18-19.

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“People were expecting a stronger labor market report,” said Charlie Ripley, senior market strategist for Allianz Investment Management in Minneapolis. “It was a little bit weaker on the margin but nonetheless it’s going to give the Fed some food for thought as they ... debate how they’re going to shape policy for the upcoming year.”

Energy shares .SPNY fell 0.6 percent, supported by rising oil prices as Saudi Arabia and other producers in OPEC, as well as allies like Russia, agreed to reduce output to drain global fuel inventories and support the market.

In a closely watched initial public offering, shares of biotech company Moderna Inc MRNA.O fell 19.1 percent in their debut.

Declining issues outnumbered advancing ones on the NYSE by a 2.08-to-1 ratio; on Nasdaq, a 2.63-to-1 ratio favored decliners.

The S&P 500 posted 13 new 52-week highs and 38 new lows; the Nasdaq Composite recorded 12 new highs and 238 new lows.

On Thursday, 1,322 stocks made new 52-week lows on the Nasdaq and NYSE on Thursday, the most since January 2016.

About 8.7 billion shares changed hands in U.S. exchanges, above the 7.9 billion daily average over the last 20 sessions.