Russia has not yet delivered advanced S-300 missiles to Syria, despite rather vague Syrian indications to the contrary, two Russian media outlets reported on Friday.

The Russian business daily Vedomosti said that it was unclear whether or not the air-defense systems would be delivered this year, while the daily Kommersant reported that the S-300 missiles would only be delivered in the second quarter of 2014. According to Kommersant, the systems would need another six months of testing and training before they become operational.

The Lebanese newspaper al-Diyar reported Friday that Israel had succeeded in thwarting the missile deal by threatening to start an all-out war should Russia deliver the S-300s to the embattled Bashar Assad regime.

The report also claimed that Russian President Vladimir Putin offered to compensate Assad with the delivery of other “effective and powerful weapons,” including modern aircraft and helicopters, to use against the Syrian rebels. According to al-Diyar, Putin also passed a message to Assad saying that the entry of Hezbollah into the Syrian conflict was not helpful. Hezbollah has a reported 5,000-7,000 gunmen now fighting with Assad’s forces.

Israeli sources said Thursday that Syria has only paid for one-third of the S-300 contract. They added that, even if the deal is eventually honored, it would take months for the S-300 batteries to be operational.

“It is not clear to me that the Russians are interested in transferring the weapons. Right now, it’s more of a threat,” said Ehud Ya’ari, Channel 2′s veteran, well-connected commentator.

In remarks erroneously attributed to Assad on Thursday, the Syrian president was said to have boasted in a TV interview that his country had received a first S-300 shipment from Russia, and to have asserted that “the rest of the load will arrive soon.” Israeli officials immediately said he was lying and bluffing.

What Assad actually said in the interview, on Hezbollah’s al-Manar television broadcast Thursday night, was that Russia had fulfilled some of its weapons contracts recently, but he was vague on whether this included the advanced air-defense systems. He said Prime Minister Benjamin Netanyahu’s visit to Russia two weeks ago, to plead that the S-300 deliveries not go ahead, would have no effect.

Russia’s declared intention to deliver the sophisticated systems, which can intercept fighter jets and cruise missiles, has created a tense standoff between Israel, Syria, and Russia, with Israel threatening to do “whatever it takes” to prevent the weapons being deployed, and Syria responding that it would retaliate in kind for any Israeli strike.

Israeli media reports said Netanyahu had warned Putin of a descent into war should Russia make the delivery. Netanyahu said that if acquired by Assad, the S-300 “is likely to draw us into a response, and could send the region deteriorating into war,” Channel 2 reported.

Aside from the unique strategic capacities that the S-300 air-defense missiles would afford Syria, putting planes taking off from central Israel and its main international airport within the missiles’ range, Jerusalem also fears that the system could fall into the hands of terror groups like Hezbollah.