A Russian warship, the Caesar Kunikov, which heightened tensions between Turkey and Russia after its “provocative” passage through Istanbul’s Bosphorus late last year, traversed the strait once again on April 19.Russian soldiers on board were seen taking shelter as the Turkish Coast Guard followed the ship along the Bosphorus. The warship later headed toward the Black Sea.The Caesar Kunikov’s previous passage through the Bosphorus en route to the Mediterranean on Dec. 6, 2015, infuriated Turkey after a Russian soldier on board was seen holding a ground-to-air missile.“This is a provocation. This is a passage of harassment,” Turkish Foreign Minister Mevlüt Çavuşoğlu said at the time.