Sea-based drones have attacked Russian navy ships near the Black Sea port of Novorossiysk, a key hub for the country’s oil exports.

Ship movements were temporarily halted, said the Caspian Pipeline Consortium, following the first Ukrainian attack on one of the main Russian commercial ports.

The attack reportedly damaged a Russian naval ship, the Olenegorsky Gornyak. Footage circulating on social media showed a listing ship in the aftermath of the attack.

Tankers were loading as normal at the port which was not damaged in the attack, said the CPC. The ship movement ban was lifted at 10.40am Moscow time, it said.

Staff and contractors were “focused on visual detection of unmanned surface watercraft and immediate notification if detected,” said the CPC.

It operates the 1,500km pipeline transporting Kazakh crude, which is not subject to G7 sanctions. The pipeline carries oil to the port where it is loaded on tankers.

The Russian emergency services reported explosions early on Friday in and around Novorossiysk, said Russian news agency RIA Novosti.

The attack follows a series of attacks on port facilities in the Black Sea after Russia pulled out of the grain export deal last month.

Russia earlier this week launched a new attack on the southern port of Izmail, which has become one of the main grain export routes out of Ukraine since the collapse of the deal.

Izmail, a port on the Danube River which acts as the border between Ukraine and Romania, was hit with drones that damaged port infrastructure and grain silos, according to Ukrainian officials. The defence ministry said 40,000 tons of grain were damaged.

The port was also attacked a week ago despite previously being considered safe owing to its close proximity to Nato member Romania. That attack led to freight rates increasing and some shipowners avoiding the area in the southern part of the Odesa region.