The US oil company ConocoPhillips has yet to clean up the platform that?is contaminating China's Bohai Sea,?and has been urged?to apologize to the public for its laggard response by Chinese authorities.

A ship cleans up the leaking oil near the platform C in the Bohai Sea, China. [CFP]

The North China Sea branch of the State Oceanic Administration (SOA)?has asked COPC to explain the reason why it failed to clean up oil-based mud on the seabed timely and urged it to make an apology, according to the branch Wednesday.

The company, which operates the field in partnership with the China National Offshore Oil Corporation, says it has more than 900 personnel and 30 vessels working on the response, but they had to suspend the operation when tropical storm Muifa hit the area yesterday.

SOA criticized ConocoPhillips miss a deadline for recovering the oil-based mud leaked from Platform C of Penglai 19-3 oilfield last week.?New mud was also found during the clean-up work.

The COPC first reported the two oil spills in the Penglai 19-3 oilfield to authorities in June. The oil spills washed up on beaches in the northern Hebei Province and northeastern Liaoning Province. The spills have been blamed for losses in the provinces' tourism and aquatic farming industries.

Oil-drilling operations in the field are jointly conducted by ConocoPhillips China and the China National Offshore Oil Corporation (CNOOC), the country's largest offshore oil producer.