The US says it has seized a second tanker in the Caribbean after saying it apprehended a Russian-flagged vessel linked to Venezuelan oil in the North Atlantic.

The UK military supported the US operation to seize the tanker in the Atlantic with air surveillance and a navy ship, the Ministry of Defence says.

The US head of homeland security says the US Coast Guard conducted "back-to-back" boarding of two "ghost fleet" ships.

Earlier, several military aircraft were tracked heading towards the vessel in the North Atlantic, the Marinera. Footage shared by Russian media also appears to show a helicopter close to that ship.

Moscow says the tanker was only temporarily flagged to Russia, and that "no state has the right to use force against vessels properly registered in other countries' jurisdictions".

The ship is accused of breaking US sanctions and shipping Iranian oil - it's historically transported Venezuelan crude oil, but reports say it's empty at the moment.