Russia has stepped up its military withdrawal from Syria, removing vehicles and containers from its key Tartous port on the country’s Mediterranean coast, analysis by BBC Verify suggests.

After the fall of the Assad regime in December, verified footage showed columns of Russian vehicles moving north towards the port. Satellite images subsequently showed military hardware being stored there.

But new images published on Wednesday by Planet Labs showed that much of the material has now disappeared, after the departure of vessels linked to the Russian military.

It comes as Russian officials held “frank discussions” with the new government in Damascus, Reuters reported on Wednesday.

There have been reports that the new Syrian government has cancelled Russia’s lease at the port – but government departments contacted by the BBC would not confirm a final decision had been made.

Tartous has been a key base for Russia in recent years, allowing it to refuel, resupply and repair vessels in the Mediterranean. But warships previously docked at the port have not appeared in satellite images since the collapse of the Assad regime – which Moscow backed throughout the Syrian civil war.

The Kremlin has signalled its desire to retain control over the base, and said in December that it was speaking to the new authorities about maintaining a presence there.

However, evidence suggests that Moscow has now decided to move valuable equipment away from the port. Satellite images have also shown Russian hardware being removed from the nearby Hmeimim airbase for several weeks.

Two vessels – Sparta and Sparta II – docked at Tartous on 21 and 22 January, ship tracking sites showed. Both vessels are owned by Oboronlogistika LLC – a shipping company which operates as part of the Russian ministry of defence.

Both ships are sanctioned by the US and have been linked by Ukraine to the transportation of Russian arms. They are roll-on/roll-off vessels that can carry vehicles.

Sparta II departed the port by Monday, according to data from the tracking website MarineTraffic. Satellite images also revealed that a large quantity of military vehicles previously parked near the vessel were no longer there.

The signal of the ship’s onboard tracker was briefly picked up by MarineTraffic on Tuesday morning, showing it was travelling west through the Mediterranean near the coast of Cyprus. But since then, no signal has been received, suggesting the tracker may have been turned off.

On Wednesday, satellite images showed another vessel – identified by experts as the Sparta – had also left the port. The images also show a large quantity of containers parked nearby had been removed.

A signal from Sparta’s onboard tracker has not been detected since it docked at Tartous – suggesting it may have been turned off as well.

The International Maritime Organisation (IMO) requires all ships over 300 gross tonnes to broadcast their signal at all times, except in some limited circumstances.

Ships may choose to turn off their tracking signal for legitimate reasons – such as when navigating high-risk piracy zones. But according to Nato it could also suggest the vessel is trying to “conceal illegal activities”.

Maritime expert Frederik Van Lokeren, a former Belgian navy lieutenant and analyst, said he was “highly confident” the vessel that had left the port was Sparta, based on satellite images.

BBC Verify has previously monitored Sparta and the area where it had been docked is now empty.

It is unclear where exactly the ships are heading. Mr Van Lokeren told BBC Verify that they could be en route to Libya, where the Kremlin already boasts a significant military presence supporting the Tobruk-based warlord Khalifa Haftar.

Last week, Ukrainian military intelligence told BBC Verify that Russian flights had transferred military personnel and equipment from Russia’s other Syrian base – Hmeimim – to airbases in Libya at least 10 times since mid-December.

However, Mr Van Lokeren also suggested that the ships could be bound for Russia, where he said there was a “large probability that the military equipment might end up being deployed on the frontline against Ukraine”.

Dmitry Gorenburg, an expert on security issues in the former Soviet Union at Harvard University, told BBC Verify that the movements suggested Russia’s presence at Tartous was coming to an end.

“I don’t know whether additional ships will be needed to remove everything or not, but to my mind that’s largely immaterial,” he said. “It’s just a question of time until Russia’s military presence at the base is concluded. We shall see what comes after.”

Graphics by Mark Edwards.