U.S. investor Warren Buffett's Berkshire Hathaway Inc continued to shed its stake in top Chinese oil producer PetroChina Inc, selling about 92.66 million shares in late August for US$136 million, according to a regulatory filing in Hong Kong.

The sale of the shares at an average price of HK$11.473 follows Berkshire's sale of 16.9 million PetroChina shares in late July.

The sale cuts Berkshire's holding of PetroChina's freely tradeable shares to 9.72 percent, or 2.05 billion shares, from 10.16 percent.

PetroChina's share price has risen about 35 percent over the past year on high oil prices and vigorous Chinese demand, although domestic rivals CNOOC Ltd and Sinopec Corp have seen stock price rises of 56.5 and 76.5 percent over the same period.

Buffett earlier this year rejected a Berkshire shareholder's proposal to sell the PetroChina stake because of its parent's ties to Sudan. That decision also won support at a shareholder's meeting in May.