UPDATE 1-Bayer offers new concessions to win EU approval for Monsanto deal

* EU's deadline to conclude antitrust review now April 5

* Bayer says has offered "very significant" remedies

* Says is confident they fully address EU's concerns (Adds Bayer statement, background)

BRUSSELS/FRANKFURT, Feb 5 (Reuters) - Bayer has offered additional concessions to European regulators regarding its $63.5 billion bid for U.S. rival Monsanto in an antitrust review that will now be extended to April 5.

The proposed remedies "are very significant and we are confident they fully address the European Commission's concerns," Bayer said in a statement.

The European Commission said that the deadline for it to conclude its antitrust investigation had been postponed to April 5 from March 12 previously.

Bayer maintained it was still aiming to wrap up the deal "in early 2018".

Both the EU Commission and Bayer declined to say what assets Bayer had offered to put on the block.

The German company struck a deal with BASF in October last year to sell seed and herbicide businesses for 5.9 billion euros ($7.36 billion) but has said it was prepared to do more to gain EU approval. ($1 = 0.8020 euros) (Reporting by Foo Yun Chee and Ludwig Burger; Editing by David Goodman/Keith Weir)