Dow plunges over 600 points amid concerns over Ukraine crisis

U.S. stocks fell sharply on Thursday as investors have been haunted by the ongoing Ukraine crisis.

The Dow Jones Industrial Average decreased 622.24 points, or 1.78 percent, to 34,312.03. The S&P 500 dropped 94.75 points, or 2.12 percent, to 4,380.26. The Nasdaq Composite Index shed 407.37 points, or 2.88 percent, to 13,716.72.

Nine of the 11 primary S&P 500 sectors ended in red, with technology and communication services down 3.07 percent and 2.96 percent, respectively, leading the laggards. Consumer staples and utilities rose 0.91 percent and 0.06 percent, the only two gaining groups.

The market weakness came as Wall Street worried about the Ukraine tensions, experts noted.

On the economic front, U.S. initial jobless claims, a rough way to measure layoffs, registered 248,000 in the week ending Feb. 12, an increase of 23,000 from the previous week's revised level, the Department of Labor reported on Thursday. Economists polled by The Wall Street Journal had forecast initial jobless claims to total a seasonally adjusted 218,000.

U.S.-listed Chinese companies traded mostly lower on Thursday with nine of the top 10 stocks by weight in the S&P U.S. Listed China 50 index ending the day on a downbeat note.

On Wednesday, U.S. equities ended mixed with the Dow and the Nasdaq finishing modestly lower, while the S&P finished modestly higher, as investors digested the Federal Reserve's January meeting minutes.