LUXEMBOURG, Sept 12 (Reuters) - Luxembourg Prime Minister Xavier Bettel said on Thursday that there were currently no grounds for the bloc to agree to delay Brexit again should Britain request an extension.

Bettel's comments put him together with France's Emmanuel Macron among the more hawkish EU leaders who will debate conditions and length of any extension to Britain's current departure date of Oct.31 when they meet for a summit in Brussels on Oct.17-18.

"We see no extension for Brexit, when there is no reason to," Bettel said. "At the moment, there is no reason to give an extension."

"When there are concrete reasons ... we will discuss whether we will give a new mandate or a new extension, but that is not the case at the moment," he said. "As long as there aren't any concrete proposals, there is no reason for us to reopen anything." (Reporting by Michele Sinner, Writing by Gabriela Baczynska Editing by John Chalmers)