ConocoPhillips ( COP - news - people ) China operates offshore wells in the Bohai's Penglai 19-3 oil field in partnership with state-run China National Offshore Oil Corp. ( CEO - news - people ) The two spills, which occurred in June, covered (840 square kilometers) 324 square miles, drawing criticism from environmentalists and local media, which in turn has pressured the government to take a stern, public line.

The North China Sea branch of the State Oceanic Administration said ConocoPhillips "admitted" Saturday that there were nine oil leak sites on the seabed on the northwest side of the C Platform of the Penglai 19-3 oil field. It provided no further details and said it has asked the company to conduct a thorough investigation.

ConocoPhillips spokesman Rich Johnson said Sunday that the company's Chinese unit is closely monitoring and taking samples from nine "small seeps" that are appearing in a 15-meter (50-feet) -diameter area on the sea floor about 15 meters north of the C Platform.

The oil spills have deepened concern over the marine environment in the Bohai, a major fisheries region off China's northeast coast that already is suffering heavy pollution from industry and agriculture. ConocoPhillips said its tests of oil particles collected from shorelines found that only two of 56 could be traced to the oil spills. Most, it said, appeared to be from fuel oil.

Johnson said the first of the seeps was discovered on August 14 and reported to China's oceanic administration the following day. He said the source of the seeps is not new, and is likely to be related to the June 17 oil spill.

"While samples are still being analyzed, it is believed the source of these seeps is residual mineral oil-based mud associated with the June 17 release that is migrating up from shallow subsurface sand layers," said Johnson in an e-mailed response to an AP query.

Johnson said the total volume of material released from the nine seeps is about two 2 liters (0.5 gallons) a day. "Any oil droplets released from the seep area are contained and cleaned up at the surface," he said, adding that the company is developing plans to stop the seeps.

Altogether, the company says about 115 cubic meters (700 barrels) of oil and 400 cubic meters (2,500 barrels) of mineral oil-based drilling mud, used as a lubricant for drilling, were released by the two spills.

Johnson said that as of Sunday, ConocoPhillips has cleaned up about 90 percent of the total volume of mineral oil-based drilling mud, or 369 cubic meters (2,300 barrels), released by the June 17 spill.

ConocoPhillips China on Friday apologized for the oil spills and said the cleanup from the leaks is almost complete, with minimal impact to the environment.