Russia has stepped up the supply of sophisticated arms and equipment as well as sent a fleet of warships to Syria in a move widely seen as aimed at securing its naval base in the port of Tartous as the Damascus regime is continuing its violent crackdown against dissent.

However, Israeli reports say Russia is helping Syrian President Bashar Al Assad to prevent a possible imposition of a “no-fly” zone over the country as the first thrust of a US-led Western initiative for what could not but be a regime change in Damascus.

No official of the administration of US President Barack Obama has confirmed that there is a plan for a no-fly zone over Syria.

Tommy Vietor, a spokesman for the National Security Council, said on Friday Washington was working with allies “regarding next steps towards a Syrian-led political transition” without Assad. “The sooner this transition takes place, the greater the chance of averting a lengthy and bloody sectarian civil war,” he said.

On Monday, Obama and Russian President Vladimir Putin said after talks on the fringes of a Group of 20 summit in Mexico that they agreed on the need for an end to the conflict in Syria, but there was no sign of any shift in the Russian position.

Reports identify the Russian weapons reaching Syria as Pantsyr-S1 anti-air missiles capable of hitting fighter-bombers flying at an altitude of 12 kilometres and cruise missiles; self-propelled medium range anti-air Buk-M2 missiles that are capable of downing aircraft flying at Mach 32 speed; and shore-based Bastion anti-ship missiles which can hit vessels sailing 300 kilometres out to sea.

These are seen as aimed at countering sea-borne assaults.

In addition, Russia has also sent to the Syrian port of Tartous a naval force that includes landing-craft carrying Russian marines. Each craft can carry 250 marines and 500-tonne armoured vehicles, according to reports.

Russia’s naval base at Tartous is the only such facility it has set up outside Russian territory. It is vital for Russia’s access to the entire Middle East.

US officials have confirmed only that it is monitoring the movement of a Russian military cargo ship, the Nikolay Filchenkov, as it makes its way to Syria carrying weapons, ammunition and a small number of Russian troops.

According to Pentagon officials, US intelligence believes the Russians are sending the ship to help fortify its Tartous base. In any event, Russia is obliged under maritime rules to declare the cargo when it enters the Mediterranean.

CNN quoted US officials saying that it is not clear if the Russian soldiers are only to help secure and transport the cargo or if they will stay in Syria. The officials also said it is not clear how much of a threat the Syrian opposition forces pose to the naval base.

On Friday, Anatoly P. Isaykin, director of Rosoboronexport (the Russian state arms export authority), said: “I would like to say these mechanisms are really good means of defence, a reliable defence against attacks from air or sea. This is not a threat, but whoever is planning an attack should think about this.”

On Saturday, an official in the Russian General Staff told the Itar-Tass news agency: “Several warships of the Russian Black Sea Fleet, including large landing ships with marines aboard, are fully prepared to take to the sea in case it is necessary to protect the Russian logistics base in Tartous, Syria, since it is a zone of the fleet’s responsibility.”

US Secretary of State Hillary Clinton accused the Russians last week of shipping attack helicopters to Syria. Moscow countered that the helicopters were not new, but rather were refurbished under an existing contract with Syria.

Putin also spoke up: “Those who say that Russia is propping up any regime, in this case President Assad unilaterally, all those people are wrong. We have good and long relations with Syria, but we do not support either of the sides.”

Both Moscow and Beijing say that they are keen to see an end to the Syrian bloodshed, but oppose foreign intervention. They have also been saying that the best option is to support an initiative drawn up by UN-Arab League envoy Kofi Annan.

Syria also said it accepted the Annan plan, but failed to implement it and continued bombarding towns and villages. There have also been massacres of civilians that Damascus blamed on “foreign terrorists” whereas survivors pointed the finger at loyalists of the Assad regime.

The Annan plan now exists only in name.

The United Nations has suspended its monitoring mission in Syria – part of the Annan initiative – due to “intensifying violence.”

Monday’s talks in Mexico should have convinced Obama that Russia is committed to supporting the Syrian regime.

Analysts often refer to Russia’s arms sales to Syria and its naval base at Tartous to explain Moscow’s staunch support for the Damascus regime. However, this argument does not explain why Moscow is overlooking the negative impact that its position has on the country’s relations with the United States, the European Union and the majority of the Arab states.

After his talks with Obama in Mexico, Putin offered a reason.

“We believe that nobody has the right to decide for other nations who should be in power and who should not,” Putin told reporters. “It is not changing the regime that is important, but that after changing the regime, which should be done constitutionally, violence is stopped and peace comes to the country,” he said.

Konstantin von Eggert, political commentator for Kommersant FM radio in Moscow, explains it further. “The explanation has a lot to do with Russia’s domestic policies and the obsessions of the Russian political class,” Von Eggert writes on the British Broadcasting Corporation website.

“By standing up for Damascus, the Kremlin is telling the world that neither the UN, nor any other body or group of countries has the right to decide who should or should not govern a sovereign state.

“Ever since the fall of Slobodan Milosevic in 2000, but especially after the 2004 ‘Orange Revolution’ in Ukraine, the Russian leadership has been obsessed with the idea of America and the EU engineering the overthrow of governments that, for whatever reason, they find unsuitable,” according to Von Eggert. “Putin and his team seem to be convinced that something like that could happen to Russia.”

If that is indeed the Russian mindset, then little could be expected to come out of any effort to convince Putin to cooperate with the US towards ending the Syrian crisis in a UN context. And that means the US and its allies have to exercise whatever other options they might have. Probably they do.