Russia cuts off Assad's military lifeline to leave regime out in the cold

Move by Moscow is strongest signal that support for long-time ally is on the decline

Russia will cease deliveries of arms and fighter planes to Syria until the situation in the country stabilises, an official said yesterday, a move that would ratchet up pressure significantly on Bashar al-Assad's regime.

The announcement is the strongest signal yet of Russia's hardening stance against its long-time ally, and will come as a blow to the Syrian president, who yesterday met with Kofi Annan to discuss a political initiative to bring an end to the crisis. The UN-Arab League envoy expressed optimism after the talks, saying he and Assad had "agreed on an approach" to end the bloodshed, which he would take to the opposition.

Russia is one of Syria's largest arms suppliers and the cessation of deliveries could scuttle up to $4bn in outstanding contracts. The delivery of 40 Yak-130 fighter jets agreed late last year will be affected, said Vyacheslav Dzirkaln, the deputy director of Russia's service for military co-operation.

"While the situation in Syria is unstable, there will be no new deliveries of arms there," he said on the sidelines of the UK's Farnborough Airshow, Russian news agency Interfax reported. Rosoboronexport, which holds a monopoly on Russia's arms exports, declined to comment on the report yesterday.

Russia has been accused by Western nations of propping up the Syrian regime through its arms deliveries and blocking of resolutions at the United Nations Security Council. Accusations by US Secretary of State Hillary Clinton that it was supplying a shipment of Mi-25 attack helicopters sparked a fierce war of words between Moscow and Washington. Russia says the helicopters had been supplied decades ago and were simply being serviced. Mr Dzirkaln said yesterday they would still be returned after an earlier attempt to deliver them was thwarted as the UK insurance firm withdrew cover from the ship transporting them.

In another indication that Moscow may be distancing itself from Assad, Russian foreign minister Sergei Lavrov held talks with Syrian opposition leader Michel Kilo in Moscow yesterday, claiming that his government is actively trying to work with the Syrian and various other opposition groups to implement the Annan plan.

The country's spiral into civil war has put new pressure on the international community to find a resolution to the conflict and Mr Annan said talks with the Syrian president yesterday –seen as a last roll of the dice for his peace plan – had been "candid and constructive". He did not specify what his agreed approach with Assad entailed.

With a ceasefire abandoned and 17,000 lives claimed, according to opposition tallies, Mr Annan, who flew on to Iran yesterday for further talks on the crisis, is now pushing for a political resolution.

Syrian foreign ministry spokesman Jihad Makdissi said that both Mr Annan and Assad saw the international conference in Geneva last month, which called for a transitional unity government for Syria, as an "important step" in moving forward the political process.

But observers have expressed scepticism as to whether it will be possible to reach a deal for transition to which both sides agree. The opposition and Western nations see Assad's inclusion in any future unity government as a red line, but the Syrian president indicated yesterday that he had no intention of stepping aside.

"A president shouldn't run away from a challenge – we have a national challenge now in Syria," Assad told German broadcaster ARD in an interview. "The president shouldn't escape the situation, but from the other side you can stay as president, stay in this position, only when you have the public support... of course I still have public support."