ROME, March 13 (Reuters) - The Italian government on Monday said Russian mercenary group Wagner was behind a surge in migrant boats trying to cross the central Mediterranean as part of Moscow's strategy to retaliate against countries supporting Ukraine. "I think it is now safe to say that the exponential increase in the migratory phenomenon departing from African shores is also, to a not insignificant extent, part of a clear strategy of hybrid warfare that the Wagner division is implementing, using its considerable weight in some African countries," Defence Minister Guido Crosetto said in a statement. See here for a complete list of exchanges and delays