U.S. oil giant ConocoPhillips said that it had submitted a report to China's marine authorities detailing its response to two oil leaks at the Penglai 19-3 oil field in North China's Bohai Bay.

Spilled oil can still be seen on the surface of the water near the affected area in North China's Bohai Bay, on August 22, 2011. The oil spills near Platform C at Penglai 19-3 oil field were first detected on June 4. [Xinhua]?

The company handed over the report by the deadline of Aug. 31, set by China's State Oceanic Administration (SOA), showing that the company has met the SOA's requirements to seal off the sources of the spill and eliminate the risk for further leaks.

SOA confirmed that it has received the report but said the administration still needs to conduct site inspection and expert evaluation to verify the company's conclusions, according to Xinhua.

SOA said it will scrutinize whether the company has met the requirements as it claims.

Conoco has said that about 700 barrels of crude oil and 2,500 barrels of oil-based drilling mud has leaked since the leaks started in early June.

A total of 5,500 square km of the bay's surface has been contaminated, with 870 square km seriously polluted, meaning that it is unfit for swimming and aquatic farming, according to SOA official Wang Fei.

It is "the most serious marine ecological incident in China," Wang said.

ConocoPhillips claimed on Monday that it had sealed off leaks from an oil spill and that had cleaned up 99 percent of the mineral oil-based drilling mud near Platform C at Penglai 19-3 oil field.

Although the company has worked to clean up the spills, pollutants have still been found in the bay, even after cleanup efforts were reported to be complete.

The spills have spread to beaches in Hebei and Liaoning provinces and have been blamed for losses in the local tourism and aquatic farming industries. Aquatic farmers in Hebei planned to sue COPC and claim a total of 330 million yuan (51.56 million U.S. dollars) in compensation, according to media reports.

The SOA has set up a working group to assist with compensation claims for the oil leaking in North China's Bohai bay as the time set for the ConocoPhillips to clean up the spill hits deadline day.

Concerned parties, including the government and fishermen in 16 provinces and cities in the affected area, have the right to lodge claims for compensation according to the law.