The Coastguard is assisting a Russian cargo ship listing near Portsmouth Harbour.

The vessel is at anchor in the Solent while a pilot vessel assesses its stability and cargo.

The Coastguard said it had power and was currently stable, while the 13 crew on board were reported to be safe and well.

The maritime search and rescue service has warned of severe gales and rough seas later on Tuesday, adding it was in discussions with the owners of the vessel and vessel's agent.

Navigational safety broadcasts were being issued every 30 minutes to warn shipping in the area and a tug and lifeboat were standing by.

A radio broadcast directed at the ship's crew said: "Your vessel is significantly listing and may need help.

"We have assessed the actions you have taken so far to recover from your current situation and have been unable to rectify the situation."

An RNLI lifeboat observes the Mekhanik Yartsdev. Credit: PA

The broadcast explained there were powers under UK law to order the vessel to accept a tug or other assistance until repairs were made and the ship could continue without support.

"If you fail to make adequate arrangements for assistance, they will be made for you and the cost of a tug and any other additional support will be recovered from your owners," it said.

"If we later order you to take a tug or accept other assistance using the powers of intervention and direction and you do not comply you are committing a criminal offence under the United Kingdom law."

The Coastguard later said plans were under way to take the ship, the Mekhanik Yartsdev, to a berth in Southampton Harbour.

"The vessel has its own power and as a precautionary measure it will be assisted by a pilot vessel, two tugs and escorted by an RNLI all-weather lifeboat until it's safely alongside," a statement said.

"Once berthed a surveyor will inspect the vessel's stability and cargo."