AMSTERDAM, Jan 18 (Reuters) - The European Union is sounding out investors to issue seven- and 30-year bonds for its first debt issuance of the year backing the SURE unemployment scheme, three market sources told Reuters on Monday. The EU last week sent out a request for proposals, which issuers send out to investment banks signalling their intention to bring a deal to the market, Refinitiv capital markets news service IFR reported. Spokespeople for the European Commission did not immediately respond to a request for comment. (Reporting by Yoruk Bahceli; editing by Sujata Rao)