China's state-owned CNOOC Ltd and its Canadian takeover target Nexen Inc said on Tuesday they withdrew and resubmitted their application for U.S. approval of their $15.1 billion deal, as Canada gets close to a crucial decision on whether to approve the transaction.

The energy companies said discussions with the Committee on Foreign Investment in the United States are still going on, "with a view to completing the CFIUS review process as expeditiously as possible."

They did not provide a reason for the move.

(Reporting by Jeffrey Jones; Editing by Frank McGurty)