Russia responded harshly on Thursday to confirmed reports that Israel had launched an airstrike against Syria, calling it an affront to the UN charter and a serious breach of international norms.
Syria's closest ally in the region, Iran, called the attack one of "brutal aggression" and said it was clearly an attempt to further destabilize Syria which is in the midst of a deadly civil war.
Israel itself has not confirmed the airstrike, but sources in the US and elsewhere have said the attack did take place. Further evidence suggests that the US was notified of the attack before it took place.
Reuters reports on what is known about the airstrike itself:
Details of the strike remain sketchy and, in parts, contradictory. Syria said Israeli warplanes, flying low to avoid detection by radar, crossed into its airspace from Lebanon and struck the Jamraya military research center.
But diplomats, Syrian rebels and regional security sources said the planes hit a weapons convoy heading from Syria to Lebanon, apparently destined for President Bashar al-Assad's ally Hezbollah, and the rebels said they - not Israel - hit Jamraya with mortars.
Another source who has a relative working inside Jamraya reported that a building inside the complex had been cordoned off on Wednesday employees believed it had been hit. Flames could be seen rising from the area after the attack, they said.
"It appears that there were about a dozen rockets that appeared to hit one building in the complex," the source, who also asked not to be identified, told Reuters.
"If this information is confirmed, then we are dealing with unprovoked attacks on targets on the territory of a sovereign country, which blatantly violates the UN charter and is unacceptable, no matter the motives to justify it," the Russian foreign ministry said in a statement on Thursday.
Iran's foreign minister, Ali Akbar Salehi, also condemned the Israeli strike on Syria, calling it a "blatant violation of the sovereignty and territorial integrity" of a country it considers one of its closest allies.
The Guardian adds:
It was also reported that the IDF's intelligence chief, Major-General Aiv Kochavi, arrived in Washington on Tuesday for private talks with the US chairman of the joint chiefs of staff, Martin Dempsey, at the Pentagon.
Israel has publicly warned that it would take military action to prevent the Syrian regime's chemical weapons falling into the hands of Hezbollah in Lebanon or "global jihadists" fighting inside Syria. Israeli military intelligence is said to be monitoring the area round the clock via satellite for possible convoys carrying weapons.