(Reuters) – Wall Street closed lower on Wednesday as oil and materials share prices dropped while investors remained cautious a day after deadly bombing attacks in Belgium.

The benchmark S&P 500 index fell back into negative territory for the year after closing positive on Friday for the first time in 2016.

U.S. stocks’ fading five-week rally was further diminished by comments over the past two days by Federal Reserve officials, who expressed views that suggested an appetite for more U.S. interest rate hikes than investors had anticipated.

The possibility of more than the two expected rate hikes through December has sent the dollar higher, pushing down commodity prices.

“That’s basically what’s leaning on the market today,” said Peter Cardillo, Chief Market Economist at First Standard Financial in New York. “It’s all about commodities.”

Gold and metals prices fell as the dollar strengthened.

U.S. oil prices also were also damaged after data showing a rise in U.S. stockpiles last week rekindled worries about a global glut.

Eight of the 10 major S&P sectors were lower, led by a 2.1-percent fall in the energy sector. Chevron and ConocoPhillips were among the biggest decliners. Utilities rose 0.7 percent and was the best performing sector.

The Dow Jones industrial average closed down 79.98 points, or 0.45 percent, to 17,502.59, the S&P 500 lost 13.09 points, or 0.64 percent, to 2,036.71 and the Nasdaq Composite fell 52.80 points, or 1.1 percent, to 4,768.86.

Adding to the downturn, investors were deterred by the shortened trading week ahead of the Good Friday holiday and uncertainty tied to Tuesday’s bombings in Brussels, Cardillo said.

Earnings weakness has been another concern for investors, with first-quarter S&P 500 earnings forecast to fall 6.9 percent from a year ago, according to Thomson Reuters data.

Nike shares were down 3.8 percent at $62.44 after the world’s largest footwear maker reported quarterly revenue below estimates.

Gilead Sciences was down 3.9 percent at $90.08 while Merck was up 0.09 percent. A federal jury upheld the validity of two Merck patents in a high-profile dispute over Gilead’s blockbuster cure for hepatitis C.

Gilead was the biggest drag on the S&P 500 and the Nasdaq.

Vertex Pharmaceuticals fell 7.6 percent to $80.15 after Goldman Sachs cuts its price target on the stock.

Yum Brands was up 2 percent at $80.55 after the Wall Street Journal reported that the fast-food chain’s owner was in talks with KKR about a possible sale of a 19.9-percent stake in its China business.

Volume was lighter than in recent sessions. About 6.8 billion shares changed hands on U.S. exchanges, compared with the 8.1 billion daily average for the past 20 trading days.

Declining issues outnumbered advancing ones on the NYSE by 2,257 to 771, for a 2.93-to-1 ratio on the downside; on the Nasdaq, 2,221 issues fell and 579 advanced for a 3.84-to-1 ratio favoring decliners.

The S&P 500 posted 17 new 52-week highs and no new lows; the Nasdaq recorded 21 new highs and 40 new lows.

(Additional reporting by Abhiram Nandakumar in Bengaluru; Editing by Nick Zieminski and James Dalgleish)