Russia says it has detained eight people in connection with Saturday’s explosion on a key bridge linking Russia to Crimea.
Its FSB security service said five of those held were Russians, while the others were Ukrainian and Armenian.
It says Kyiv was behind the attack but a Ukrainian official described Russia’s investigation as “nonsense”.
The news came as explosions were reported in the Ukrainian cities of Kherson, Zaporizhzhia and Nikopol.