Russia’s defence ministry said on Monday its forces struck two Ukrainian cargo vessels in the Black Sea.

The ministry said it hit fuel storage facilities at the port of Chornomorsk meant for Ukraine’s armed forces, plus a dry cargo vessel carrying military equipment. Another vessel carrying military supplies was hit south of Odesa. It also reported striking an electrical substation in the Kharkiv region.

Maritime outlets reported Moscow claimed up to four vessels hit over the weekend around Chornomorsk and the Bug Estuary. The claims have not been independently verified, and Ukraine has not confirmed the hits.

The attacks follow a strike on a Liberian-flagged civilian cargo ship at an Odesa-region port on October 3, which killed one crew member and injured three.

Ukraine’s government says Russian attacks since the invasion began have damaged or destroyed 1,173 port facilities and 274 civilian vessels. The strikes are squeezing Ukraine’s sea trade ahead of winter.