Unconfirmed videos posted on Russian social media purportedly show a fire at the port and a projectile in the sky.
"On the night of March 2, units of the Ukrainian defense attacked the Shesharis oil terminal and the naval base in Novorossiysk," the Ukrainian military wrote on Facebook.
The attack comes just days after American media reported that the United States had warned Ukraine against strikes on the country's economic interests in the port.
Ukraine struck the Shesharis terminal last November, as well as a nearby terminal that handles the bulk of Kazakhstan's oil exports. The latter terminal is partly owned by US oil companies Chevron and Exxon Mobil.
