July 21 (Reuters) - A Liberian-flagged vessel sailing from Egypt to Ukraine has been hit ‌off Romania's coast in an attack likely ‌linked to Russia's war on Ukraine, Romanian President Nicusor Dan ​said on Tuesday. This year, Russian and Ukrainian drones have repeatedly breached the airspace and territorial waters of Romania, officials in the European Union and ‌NATO member state ⁠neighbouring Ukraine have said. "State institutions are on alert and will clarify the circumstances, ‌causes and responsibilities related to ​this serious incident, most likely ​part of the ​illegal war of aggression of the ‌Russian Federation against Ukraine," Dan ​said. Russia, which ​launched a full scale invasion of Ukraine in 2022, has either denied responsibility for reported ​attacks on ‌Romania, said they were carried out by ​Ukraine, or blamed Ukrainian "provocation". (Reporting by Anna Wlodarczak-Semczuk; ​Editing by Philippa Fletcher)