U.S. stocks are opening lower as investors worry about China's ability to stem a stock market slide there.
The Dow Jones industrial average declined 132 points, or 0.7 percent, to 17,649 as of 9:35 a.m. Eastern time.
The Standard & Poor's 500 gave up 13 points, or 0.6 percent, to 2,068. The Nasdaq fell 32 points, or 0.7 percent, to 4,965.
Stocks fell 6 percent in Shanghai despite the Chinese government's latest efforts to shore up the market. Chinese stocks have plunged in the last month but are still up 70 percent over the past year.
European markets were broadly higher as talks continue on Greece's debt woes.
United Continental lost 1.5 percent after grounding all of its flights in the U.S. due to computer problems.