BRUSSELS, Nov 16 (Reuters) - European Union governments failed to give a clear opinion on Thursday on a proposal to extend by 10 years EU approval for the use of glyphosate, the active ingredient in Bayer AG's Roundup weedkiller.

A "qualified majority" of 15 of the EU's 27 countries, representing at least 65% of the bloc's population, had been required either to support or block the proposal.

This was the second time EU governments have voted on the proposal after giving no clear opinion a month ago, meaning it returns to the European Commission to decide on the next steps.

The commission could clear the extension or revise its proposal.

The previous time glyphosate's licence came up for re-approval, the EU gave it a five-year extension after EU countries twice failed to support a 10-year period. (Reporting by Philip Blenkinsop; Editing by Sudip Kar-Gupta and Bernadette Baum)