NEW YORK, Nov 5, 2007 (AFP) - US stocks opened sharply lower Monday amid skittishness following a shakeup at banking giant Citigroup amid news of multibillion-dollar writedowns, and a slide in markets in China.

The Dow Jones Industrial Average sank 118.68 points (0.87 percent) to 13,476.42 and the Nasdaq tumbled 35.94 points (1.28 percent) to 2,774.44 in the first trades.

The broad-market Standard & Poor's 500 index shed 14.44 points (0.96 percent) to 1,495.21.

The market action came after Asian stocks closed sharply lower with sentiment damaged by the subprime mortgage crisis in the US and a heavy sell-off in the Hong Kong and mainland China markets. Hong Kong shares slid five percent.

In the US, the world's biggest bank Citigroup named ex-US Treasury chief Robert Rubin as its new chairman Sunday, replacing Charles Prince who retired as it warned of massive losses from the subprime mortgage crisis.

"During these pullback periods, we are looking for some kind of an oversold reading to indicate a near-term low is at hand, and we aren't there yet," said Bob Dickey at RBC Dain Rauscher.

"Blame it on the financial stocks, many of which hit new lows again last week but still represent a big part of the total market cap (capitalization)."