Russian drones have targeted the strategic port city of Odessa in Ukraine, causing "damage", city authorities said early Tuesday.

"The enemy has just targeted Odessa and its region with attack drones," a statement posted by city authorities on Facebook said, adding that "there is damage," without providing further details.

The statement quoted the head of the military administration of the Odessa region Yuri Kruk as saying that "Ukrainian air defense forces are working," warning of the possibility of a second wave of attacks. No further details were immediately provided.

The Black Sea port of Odessa was a favorite holiday destination for Ukrainians and Russians alike before the Russian war in Ukraine began in February last year.

Since the war began, Odessa has been bombed several times by Russian forces.

In January, the United Nations Educational, Scientific and Cultural Organization (UNESCO) warned that the World Heritage city centre of Odessa was at risk.