Trading was halted on the New York Stock Exchange in the late morning because of a technical issue.
The halt occurred at about 11:30 am Eastern time today.
The exchange said in a statement that it was experiencing a "technical issue" that it was working to resolve as quickly as possible.
Before trading was halted, US indexes were lower as investors worried about China's ability to stem a stock market slide.
The Dow Jones industrial average was down 215 points, or 1.2 per cent, to 17,561.
The Standard & Poor's 500 gave up 24 points, or 1.2 per cent, to 2,057. The Nasdaq was down 73 points, or 1.5 per cent, to 4,924.
European markets were broadly higher as talks continue on Greece's debt woes.
