China's coastal city Tianjin have detected an oil belt in the waters of Bohai Bay, which is suspected as the evidence of the worsening impact of a massive oil leak that began in June.

Tianjin has reported fresh oil belts?in seawater on August 4, 2011. [Tianjin Oceanic Administration]

The suspected oil belt is about 3 kilometers long and 5 meters wide, according to the Tianjin Oceanic Administration.

"A water sample has been sent to the State Oceanic Administration and the results will come out by the weekend, possibly Friday," said Zhang Jinguo, an official at the administration on Thursday.

Whether the substance in the water is an oil belt will not be confirmed until test results are released, Zhang added.

A fisherman was the first person to notice the suspected oil belt on Monday.

Liu Fenglin, director of the press office of the State Oceanic Administration (SOA)'s North China Sea Branch, said it takes at least one day to test the water sample and officials will release the results as soon as possible.

The samples of oil belts?in seawater of Tianjin. [Tianjin Oceanic Administration]

All the three provinces and one municipality around Bohai Bay - Hebei, Shandong, Liaoning and Tianjin - have reported fresh oil belts in seawater or dried oil drops on the shore since the Penglai oil spill.

ConocoPhillips China, the operator of two leaking oil platforms in Bohai Bay, said on Wednesday that more oily mud had been found near a leaking platform, and this was likely to push up the volume of the oil spill to a new high.

The North China Sea Branch of the SOA issued a notice on Monday ordering the company to appropriately dispose of contaminants to avoid further pollution from the oil spill, which started on June 4 near Platform B of the Penglai 19-3 oilfield.