July 18 (Reuters) - Shipping grain out of Ukrainian Black Sea ports without security guarantees from Russia would carry risks because Ukraine uses those waters for military activities, the Kremlin said on Tuesday, commenting on suggestions that Turkey could protect Ukrainian grain ships.

Kremlin spokesman Dmitry Peskov told a briefing that Moscow rejected U.S. criticism of its withdrawal from a grain deal backed by Turkey and the United Nations. Russia would continue supplying grain to poor countries, he said. (Reporting by Reuters; Editing by Kevin Liffey)