BEIJING - China's major futures exchanges said on Thursday that trading fees for some futures will be raised as risks of overheating loom following days of rapid price increases and alarmingly high market turnover.

Shanghai Futures Exchange said that starting April 25, the trading fees for hot-rolled steel coils, screw thread steel and petroleum asphalt will be raised to 0.01 percent from the current 0.004 percent, 0.006 percent and 0.008 percent respectively.

Also starting April 25, Dalian Futures Exchange will raise the trading fees for iron ore and polypropylene to 0.009 percent.

By the end of Thursday's trading, the dominant contract for screw thread steel RB1610 rose by the daily limit for two consecutive trading days, raising its total gain so far this week to 12.7 percent.

Trading volume of RB1610 on Thursday reached 22.36 million lots, or 223.6 million tons, which was valued at 605.6 billion yuan ($93 billion). That dwarfed the combined market turnover of the Shanghai and Shenzhen stock markets, which stood at 542 billion yuan.

Investors are betting on continued price rebounds as the general economy has shown tentative signs of warming while industry data offered hope of improved supply-demand curves.

Official statistics show that China's steel production in the first quarter was flat year on year at 262 million tons, while the exports in March surged 29.6 percent to 9.98 million tons. In the first quarter, China's steel imports fell 3.3 percent.

The government obviously wanted to prevent huge market swings that could derail the nascent economic recovery.

Shanghai Futures Exchange said in a separate statement issued on Thursday, "Due to a volatile domestic and international economic and financial situation, there are many uncertainties affecting market operations. We are seeing brisk transactions and increased price fluctuations. Investors should be reminded to carefully assess market information and invest rationally."