BEIJING, Nov. 30 (Xinhua) -- Chinese share prices were sharply lower on Friday as the benchmark Shanghai Composite Index plunged 2.63 percent following Thursday's strong gains.

    The key Shanghai index, which covers both A and B shares, fell 131.55 points to close at 4,871.78 points. The intraday low was 4861.86 points.

    The benchmark index surged 4.16 percent to 5003.33 points on Thursday, ending three consecutive days of decline.

    The Shenzhen Component Index on the smaller Shenzhen Stock Exchange ended at 15,637.66 points, down 1.77 percent, or 281.62 points.

    Profit taking sank blue chips. PetroChina, the country's largest oil producer, fell 4.63 percent to 31.52 yuan, while Sinopec lost 3.25 percent to 21.12 yuan.

    The Bank of China shrank 1.98 percent to 6.45 yuan, and China Merchants Bank lost 2.24 percent to 39.25 yuan. CITIC Securities, the country's largest listed security brokerage, tumbled 4.25 percent to 83.89 yuan.

    "The rebound on Wall Street during the past two days boosted the key Shanghai index on Thursday, but profit taking sunk shares on Friday," Li Feng, a senior equity strategy analyst with China Galaxy Securities, said.

    He said the downward trend was led by the heavyweights, PetroChina in particular, which accounted for a quarter of the total weight of the benchmark index. The share price of PetroChina hit its lowest mark on Friday since its debut on the Shanghai bourse on Nov. 5.

    "Some analysts believe that some blue chips are overvalued, so the correction is reasonable. The market fluctuations may continue through the end of this year because it takes time for investors to regain full confidence in the market," said Li.

    The combined turnover of the two bourses of 100.47 billion yuan on Friday is shy of half of the peak during the mid-October.

    Many Chinese investors experienced a hard time in the past six weeks, during which the Shanghai Composite Index tumbled from 6,092 points to 4,803 points on Wednesday.

    "Because the confidence of investors is relatively weak, the stock market is easily affected by external factors," added Li.

    He said the trend of next year's domestic stock market would be influenced not only by the corporate earnings of listed companies, but also the growth of China's gross domestic product and foreign trade and the recovery pace of the U.S. economy. (One U.S. dollar is equal to 7.3997 yuan)