A new oil spill was reported off China's northern coast on Tuesday, the third such incident on the Bohai Sea in less than two months.

All the three spills involve China National Offshore Oil Corporation (CNOOC), the country's largest offshore oil producer.

The new leak occurred in CNOOC's Suizhong 36-1 oilfield at about 1:30 a.m. when the centralized control system of the oilfield's central platform broke down, the State Oceanic Administration (SOA) announced in a press release, citing a report submitted by CNOOC's Tianjin branch.

It is estimated that about 0.1 to 0.15 cubic meters of oil was leaked, polluting an area of one square km, the press release said.

CNOOC has used oil absorbent mats and sprayed oil dispersant to clean up the sea, it said.

SOA has also dispatched a helicopter and used satellite remote sensing to monitor the development of the spill, it added.

Last month, two oil spills took place on the Bohai Sea, both at the Penglai 19-3 oilfield, which polluted an area of 840 square km. The field is being operated by ConocoPhillips China, a subsidiary company under U.S. energy giant ConocoPhillips, in a joint development agreement with CNOOC.

ConocoPhillips was responsible for the oil spills, which caused "a certain level" of damage to the nearby oceanic environment, the SOA has said.

ConocoPhillips announced last week that the oil spills had been contained and the clean-up was almost finished.