Wall Street was bracing for a volatile start to trading in 2016 after shares in China crashed by 7% on the first full business day of the new year, causing activity on mainland Chinese stock exchanges to be halted by regulators.

The Dow Jones futures index fell by more than 300 points in pre-market activity Monday as investor anxiety appeared to be sparked by the China plunge and rising tensions in the Middle East among Iran, Saudi Arabia and other key nations.

China’s collapse appears to have been triggered by weak new data concerning purchasing managers’ forward business intentions. The data indicated the tenth successive month of pessimistic outlook.

Shares in Shanghai and Shenzhen opened weaker on Monday morning and trading was automatically halted for 15 minutes shortly after midday local time, after indexes had fallen by 5%. According to reports, the circuit breaker’s use for the first time may have further spooked investors. And an hour later, when losses had reached 7%, trading was automatically halted for the remainder of the day.

Many China-traded media shares recorded falls greater than the market average. Huayi Brothers was down 7.55% at RMB38.35; Wanda Cinema Line was down 10% at RMB108; Huace Media was down 9.37% at RMB27; and Enlight Media was down 9.84% at RMB27.31.

The Hong Kong stock market stayed open, but was battered by the effect of the mainland slide. By mid-afternoon Monday the Hang Seng Index was down some 2.6%. Hong Kong traded media stocks had mixed performances. Alibaba Pictures Group was up 1.56% at HK$1.95; IMAX China was down 1.92% at HK$53.6; social media giant Tencent was down 3.1% at HK$149.4; Fosun International was down 3.64% at HK$11.66.

Chinese share markets saw enormous gyrations last year, with a huge run up of prices until July that was followed by a violent crash. Share values have since largely recovered, but the ongoing effects of the government’s maladroit stabilization measures continue to weigh on the markets and may have contributed to Monday’s selloff.

Regulators also unveiled new restrictions, with a halt to IPOs on the so called ‘New Third Board,’ properly known as the National Equities Exchange and Quotation system.

Cynthia Littleton contributed to this report.