ANKARA (Reuters) - President Tayyip Erdogan said on Wednesday that Turkey had not yet received any concrete proposals to address its concerns over Finland and Sweden's NATO membership bids, which Ankara objected to on grounds that they support groups it deems terrorists.

       Speaking in parliament, Erdogan said Turkey wanted to see a "sincere" approach from the two Nordic countries regarding its concerns, adding Ankara would not change its view unless it saw concrete and binding steps.

       He also said Turkey's objection to Stockholm and Helsinki's membership bids was not "opportunism" but rather a matter of national security.

       (Reporting by Tuvan Gumrukcu and Ezgi Erkoyun; Editing by Jonathan Spicer)