BEIJING -- Shares of Sinopec, China's top refiner listed in both Shanghai and Hong Kong, opened to tumble on Monday following Friday's deadly oil pipeline blasts in east China's Shandong province.

A-share of Sinopec in Shanghai opened at 4.85 yuan (79 US cents) per share, down 3.96 percent from Friday's closing price.

H-share of Sinopec opened at HK$6.8 (87 US cents), down nearly 3 percent from Friday's closing.

Death toll from Friday's Sinopec oil pipeline blasts rose to 52 as of 1 pm. Sunday after four bodies were found at the scene, rescuers said. Reports and investigations showed that 11 others were missing in the deadly accident, the rescue headquarters said.

In a filing on Sunday to both the Shanghai and Hong Kong stock exchanges, Sinopec said its crude oil pipeline in the Qingdao Economic and Technological Development Zone in Shandong ruptured on Friday morning, resulting in oil leakage and some crude oil entered into the covered municipal drainage trench and flowed into the frith of the bay area.

The refiner "expressed its sincere condolences to the victims and extended its deepest sympathy to the injured persons and their families of this major casualty accident," said the statement.

The pipeline that occurred oil leakage was the Donghuang II Pipeline. The pipeline was completed in construction and put into operation in July of 1986. It was 248.52 km long with a capacity of 10 million tonnes per annum.

The Chinese government had sent an investigation team to fully investigate the cause and related matters of the accident, and Sinopec will actively cooperate with the relevant investigations, it added.

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