KYIV, May 27 (Reuters) - Ukraine's largest steelmaker Metinvest on Friday said it was concerned that Russia may use several ships stranded in the southeastern city of Mariupol to "steal and smuggle metallurgical products belonging to Metinvest Group." The statement offered no evidence to back up the allegation that Russian forces were planning to do so. Metinvest said in a statement that five ships, carrying a total of 28,000 tonnes of steel earmarked for export, were stranded in the city when Russian forces arrived and that it would undertake "every possible legal effort" to defend its interests. (Writing by Conor Humphries) ((conor.humphries@thomsonreuters.com; +353 1 236 1915;)) The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.