ConocoPhillips China said it plugged all the oil leak sources permanently, and the leaks won't have substantial impact on China's northeastern coast, the Beijing Times reported.

The claim came just before the Aug 31 deadline set by China's marine authorities State Oceanic Administration (SOA) for the firm to seal off oil leaks and clean off polluted areas.

The SOA said ConocoPhillips would face "enhanced supervision" if it failed to meet the deadline, but it didn't specify on the further actions.

By Sun Yuanqing