German Chancellor Angela Merkel said on Monday there was not much time left for a debt deal to keep Greece in the euro zone and that Europe was prepared to show solidarity if Athens implemented economic reforms. Merkel said the Greek crisis had played a role in a discussion of risks to the world economy at a summit of Group of Seven (G7) industrialised democracies but she dismissed comparisons with the collapse of U.S. investment bank Lehman Brothers in 2008. "We want Greece to remain part of the euro zone but we take the clear position that solidarity with Greece requires that Greece makes proposals and implements reforms," she said.