Syrian rebels under siege near the Lebanese border pleaded for help on Thursday against government troops and their Hezbollah allies as a confident President Bashar al-Assad spoke of having new Russian missiles.
Though Moscow contradicted suggestions he had taken delivery of an entire, long-range S-300 anti-aircraft system which alarms Israel, Russia's plan to send them highlighted the international confrontation brewing over Syria, even as Moscow and Washington work together for a peace conference between the warring sides.
With Iran and its Lebanese partner Hezbollah also rallying to Assad's defense and his Western-backed Syrian opponents mired in squabbles, the president was quoted sounding confident of his position at home and abroad. He would attend talks in Geneva, he said, but he expected to keep fighting the revolt.
Among his enemies on the battlefield, rebels in the besieged border town of Qusair warned that it could be wiped off the map and hundreds of their wounded might die if no help came soon.
"The town is surrounded and there's no way to bring in medical aid," Malek Ammar, an opposition activist in the town, told Reuters over an Internet link, adding that about 100 of the 700 wounded needed bottled oxygen to keep breathing.
"What we need them to do," he said of other rebel units, "is come to the outskirts of the city and attack the checkpoints so we can get routes in and out of the city.
There was little immediate sign, however, of military relief or of a negotiated settlement that might end the fighting.
Harsh words from Moscow against the Syrian opposition's insistence on Assad's removal as a precondition for talks, and Russian criticism of Washington for considering a no-fly zone to help the rebels, underlined the geopolitical stakes in the war.
An exchange of fire across the Turkish border on Thursday was a reminder that all Syria's neighbors risk being sucked in to a regional conflict.
Rebels at Qusair and comrades encircled near Damascus, who also appealed for reinforcements, face shortages of weapons. Fears of the Islamists in the rebel ranks have deterred Western powers from supplying them, despite wanting to see Assad fall.
The result, after two years of fighting and more than 80,000 deaths, has been an increasingly sectarian stalemate in which Assad has lost control of swathes of territory but remains in power. Taking back Qusair would help secure access from Damascus to the coastline populated by his minority fellow Alawites.
For the rebels, mostly drawn from the Sunni Muslim majority, Qusair secures supply lines from sympathizers in Lebanon and from further afield, notably Sunni-ruled states in the Gulf.
In a statement, the rebel commanders at Qusair warned of dire consequences if help fails to arrive for men who have been fighting house to house for over a week against a force armed with tanks and rocket-launchers and spearheaded by Lebanese fighters from Hezbollah, seasoned in a 2006 war against Israel:
"If all rebel fronts do not move to stop this crime being led by Hezbollah and Assad's traitorous army of dogs ... we will soon be saying that there was once a city called Qusair."
Shells were landing by the minute and the attackers seemed to be advancing more quickly after seizing a nearby air base.
Elsewhere, rebels blockaded in eastern suburbs of Damascus known as eastern Ghouta appealed for help on Facebook, saying Assad's forces were "preparing to commit more massacres".
They pointedly said they held not just fellow guerrilla units responsible for coming to their aid but also the Syrian National Coalition, whose exile members have spent a week arguing in Istanbul over how to present a common front at the talks Washington and Moscow are trying to arrange in Geneva.
An attempt to heal rifts between Islamist and liberal wings of the opposition by offering liberals more seats on the exile body that Arab and Western powers want to form a transitional government failed to mend fences with fighters inside Syria.
Despite an offer by the Sunni Islamists who dominate the Coalition to give a liberal bloc more seats, the haggling continued, to the frustration of Turkey, Gulf Arab states and Western diplomats who have hoped that the body can use the peace conference to start taking responsibilities.
Inside Syria, the body which groups very diverse fighting units issued its own response, demanding that it be granted half the seats in the Coalition - a reflection of persistent mistrust between fighters and exiles.
Russia, an ally of Damascus since the Cold War when Assad's late father was in power, scoffed at the opposition's demands for a deadline to secure the president's removal as a condition for them attending the talks. Russian, U.S. and U.N. officials will hold a planning meeting next Wednesday.
Russian Foreign Minister Sergei Lavrov said the Coalition seemed to be "doing everything they can to prevent a political process from starting ... and achieve military intervention".
"We consider such approaches unacceptable," he said, referring to rebel pleas for Western weapons which persuaded Britain and France this week to end an EU arms embargo.
His ministry also chided Washington for keeping open the possibility of imposing a no-fly zone. It said that "cast doubt on the sincerity of the desire of some of our ... partners for success in international efforts" to end the war.
Rivalry between Russia and Western powers has deadlocked previous international efforts to end the fighting but fears that the conflict was spreading - notably with Israel bombing Syria, Iranian-backed Hezbollah declaring it would fight for Assad and reports of troops using chemical weapons - prompted Washington and Moscow to launch the joint call for a conference.
In a television interview not yet broadcast but quoted by a Lebanese newspaper, Assad said he planned to go to the "Geneva 2" meeting but was unconvinced of a fruitful outcome.
He underlined the extent of international resources he can call on, despite Western sanctions, by saying Syria had received a first shipment of S-300 missiles from Russia under a deal signed before the conflict and which Israel fears could pose a threat to aviation over its own airspace.
A source close to Russia's defense ministry said, however, that the "hardware itself" had yet to be delivered to Syria, where Moscow has a Mediterranean naval base. But, the source added, "certain parts of the contract may have been fulfilled".
The United States has urged Russia not to supply the system. As with Assad's existing stocks of heavy weaponry, including chemical warheads, neighboring states are concerned not only that the existing government might use them but that they could fall into the hands of militant groups fighting to remove it.