No newly-formed oil belt was detected in the past two days in north China's Bohai Bay from ConocoPhillips' platforms in the Penglai 19-3 oilfield, the State Oceanic Administration (SOA) said.

However, new spots of visible oil spills could still be found around platform C, the SOA said in a statement on Sunday.

It is estimated that about 4.51 liters of oil leaked into the sea on Saturday, a slight drop from 6.56 liters from Thursday.

No oil clean-up work was done on Friday and Saturday due to the strong winds and rough conditions at sea, the statement said.

ConocoPhillips China, a subsidiary of U.S. energy giant ConocoPhillips, first reported spills to authorities in June. The oil spills have polluted more than 5,500 square km of sea water in the Bohai Bay since June.

The oil spills have spread to beaches in Hebei and Liaoning provinces. The spills have been blamed for losses in the provinces' tourism and aquatic farming industries.

The company on Aug. 31 submitted a report to the SOA claiming that it had screened out all potential sources for oil spills and blocked all oil leaks.

After days of evaluation, however, the SOA said on Sept. 2 that ConocoPhillips had failed to complete the clean-up.