New York, April 22 : US equities ended sharply lower on Tuesday as Monday's steep sell-off in oil futures rattled investors. The Dow Jones Industrial Average plunged 631.56 points, or 2.67 per cent, to 23,018.88. The S&P 500 decreased 86.6 points, or 3.07 per cent, to 2,736.56. The Nasdaq Composite Index fell 297.5 points, or 3.48 per cent, to 8,263.23, Xinhua reported. All 11 primary S&P 500 sectors closed lower, with technology down 4.1 per cent, the worst-performing group. Oil futures continued to struggle on Tuesday, following a historic drop in the previous session. The West Texas Intermediate for May delivery rebounded to positive territory on Tuesday, its expiration day. Prices crashed to an unprecedented settlement of -37.63 USD a barrel on Monday. The new front-month June contract plunged more than 43 per cent to close at $11.57 a barrel on Tuesday, and the international benchmark Brent crude also tumbled. Traders paid close attention to the bizarre movement in oil futures as they grew concerned that deep losses for the energy industry would hit the US economy even further, experts noted. /IANS