Russian President Vladimir Putin said Russian strikes on Ukrainian infrastructure and a decision to freeze participation in a Black Sea grain export program were responses to a drone attack on Moscow's fleet in Crimea that he blamed on Ukraine.

Putin told reporters on Monday that Ukrainian drones had used the same marine corridors that grain ships transited under the U.N.-brokered deal.

Kyiv has not claimed responsibility for the attack and denies using the grain program's security corridor for military purposes. The United Nations said no grain ships were using the Black Sea route on Saturday when Russia said its vessels in Crimea were attacked.