On Friday U.S. stock indices dropped sharply as weak manufacturing data intensified concerns about China's economy.

The Dow Jones Industrial Average dropped 530.94 points, or 3.1%, to 16459.75. The S&P 500 fell 64.84 points, or 3.19%, to 1,970.89. The Nasdaq Composite plunged 171.45 points, or 3.52%, to 4,706.04.

About three quarters of the Dow Jones industrial average stocks and almost 70% of S&P 500 components were in correction territory, meaning their session lows were at least 10% below their 52-week highs. Energy stocks fell most among S&P's components.

This morning in Asia Hong Kong Hang Seng dropped 4.64%, or 1,039.92 points, to 21,369.70. China Shanghai Composite Index tumbled 8.45%, or 296.55 points, to 3,211.20. The Nikkei fell 3.63%, or 706.20 points, to 18,729.63.

China's Shanghai Composite dropped to a five-month low despite an official permission granted over the weekend for pension funds managed by local governments to invest in the stock market.

In Japan a stronger yen weighed on stocks. Officials were also cautious about weakness of China's economy.