ConocoPhillips China, the operator of two leaking oil platforms in Northeast China's Bohai Bay has resumed operations at some wells Thursday that were ordered to shut down after an oil spill.

Crews try to recover oil-based mud from the seabed near the Penglai 19-3 C platform.

The company said on its website that the operations have been approved by the State Oceanic Administration (SOA) of China.

"The company is now flowing a total of 14 production and water injection wells on platform B of the Penglai 19-3 oilfield back into production," said the company. "Flowing these wells reduces the overall pressure in the subsurface formation, which will assure that the seeps stop and the fault which was previously activated naturally seals."

The oil leaks at the Penglai 19-3 oilfield, first reported spills to authorities in June, have polluted an area of 3,400 square km in the Bohai Bay and have spread to beaches in Hebei and Liaoning provinces.

The SOA has ordered ConocoPhillips to halt production at platform B and C of the Penglai 19-3 oilfield since July 13 because of the slow process of cleaning up the leak.

Since Aug 3, cleanup crews have recovered 269 cubic meters of oil-based mud, enough to fill 1,700 barrels, from the seabed near the Penglai 19-3 C platform. They have also collected 70 cubic meters of an oil-and-water mixture, enough for 440 barrels, from the sea surface, the statement said.

China's marine authority urged the company to stop oil leaking and cleaning up the oil mud by the end of August.