People's Bank of China, the country's central bank, took urgent measure to provide sufficient liquidity to stabilize the stock market.

The unlimited liquidity will be injected into China Securities Finance Co Ltd (CSF), an institution that provides margin financing loan services to qualified securities companies jointly founded by Shanghai Stock Exchange, Shenzhen Stock Exchange and China Securities Depository and Clearing Corporation Limited.

The financing channels will include inter-bank lending, financial bonds, mortgage and refinancing, it said.

"The PBOC will pay close attention to the stock market and continually support CSF through multiple channels to stabilize the stock market, to keep from systematic and regional financial crisis," said a statement from the central bank on its website.

The central bank issued the statement at the Wednesday's opening when the Shanghai Composite Index, or the country’s stock benchmark index, slumped close to 3,400 points, or 7 percent, from a seven-year high of 5178.19 on June 12.

More than 1,300 companies listed in Shanghai and Shenzhen exchanges suspended their share trading on Wednesday, accounting for 45 percent of the whole, trying to avoid sharp price decline during the market turmoil.

The country's securities watchdog China Securities Regulatory Commission announced on Wednesday that the CSF will increase purchase on stocks with small and medium-sized market value, while continually buying the blue-chips – the high-valued stocks.

"The measure will increase market liquidity as currently the stock market shows liquidity squeeze due to the market panic and a rise of irrational selling," said Deng Ge, spokesman of the CSRC.

To curb the market crash, 21 securities companies injected 128 billion yuan in total to the stock pool since this week. "The current situation of these companies is stable, with sufficient capital. Their total net asset is more than 800 billion yuan. The net capital and high-quality liquid assets is more than 600 billion yuan," said Deng.

The CSRC also announced that China Financial Futures Exchange will raise the margin for selling stock index futures of the CSI 500 on Wednesday to 20 percent of the contract price from 10 percent, and up to 30 percent since Thursday, aiming to curb speculative trading and control market risk.