BEIJING - China's maritime authorities on Wednesday ordered ConocoPhillips China (COPC) to immediately suspend the operation of two of its platforms in northeast China's Bohai Bay following two oil spills, saying that the risk of more spills still exists.

The measures that COPC took to eliminate the risk of new spills since the first two spills were detected last month have been inadequate, the State Oceanic Administration (SOA) said in a statement.

"Another spill could occur at any time. This poses a huge threat to the ecology of Bohai Bay," the statement said.

A bird's-eye view of Oil Rig B of Penglai 19-3 oilfield in Bohai Bay, July 11, 2011. [Photo/Xinhua]

A subsidiary of US-based energy giant ConocoPhillips, COPC operates platforms in the Penglai 19-3 oilfield, located in Bohai Bay, under an arrangement with the China National Offshore Oil Corporation (CNOOC), China's largest offshore oil producer.

Last month's oil spills seriously polluted 840 km of sea area in Bohai Bay, sending water quality ratings in the area to their lowest level.

"COPC failed to bring the situation under full control. Its recent efforts to find the causes of the spills and stifle them have been slow," the SOA said.

The SOA has been monitoring the oilfield using remote sensing satellites and inspections. The authority found that oil continued to spill out of two of COPC's platforms for days after the spills were detected.

An initial investigation found that there were still oil belts around the two platforms, as well as signs indicating that more oil spills may occur, the SOA said.

The SOA urged COPC on Wednesday to thoroughly check its platforms in order to eradicate the risk of new spills, as well as report information regarding possible spills to the SOA in a timely manner

Liu Cigui, head of the SOA, called for extensive checks to be conducted in all offshore oilfields during a Tuesday meeting. Liu ordered intensified inspections for all offshore surveying and developing activities.

The CNOOC has recently come under scrutiny for several accidents involving its facilities, including the Penglai 19-3 spills.

An oil spill occurred on Tuesday in the CNOOC's Suizhong 36-1 oilfield, which is also located in Bohai Bay. The spill was apparently caused by a malfunction in the centralized control system of the oilfield's central platform.

About 0.1-0.15 cubic meters of oil was estimated to have been leaked, polluting an area of one square km, according to an earlier SOA statement.

CNOOC said Wednesday afternoon that all of the spilled oil has been cleaned up and that operations in the oilfield have resumed.

A fire broke out early Monday morning at a CNOOC oil refinery in the city of Huizhou in south China's Guangdong Province. The fire was put out a few hours later, with no casualties reported, according to a CNOOC spokesman.