A call to arms from Syria's rebels
Russian bombers have continued to target Syrian opposition forces, while hundreds of Iranian soldiers have been flown into Syria to help the beleaguered regime.
With opposition fighters up against regime forces - including their allies from Iran, Iraq and Hizballah - as well as Islamic State group militants, many are wondering how long the overstretched fighters can hold up against a world superpower such as Russia.
Many analysts have predicted that, after months on the offensive, rebel gains could be slowed down or contained, and opposition fighters routed.
Rebel factions are tied up in several military campaigns against a wide range of enemies on multiple fronts.
Jaish al-Fatah has been advancing slowly on the strategically important Sahl al-Ghab plain in Hama, while the Free Syrian Army's ongoing southern offensive in Daraa province has reached a stalemate.
In the Latakia mountains, rebel groups are facing heavy Russian and regime air raids on a daily basis.
Dozens, maybe hundreds, of civilians are killed each week around Damascus in Bashar al-Assad's bombing campaign with Daraya being hit by 500 barrel bombs in September alone.
Despite having laser-guided missile technology, Russia has also targeted civilian areas in opposition territory around the Latakia mountains, the Homs countryside, and Hama city.
According to activists, a Russian missile hit a bakery - frequently targeted by the Syrian regime, as masses of people queue for the basic commodity.
Eliot Higgins, investigative journalist, pointed out that Russia has been most likely using unguided bombs in its Syria campaign.
— Eliot Higgins (@EliotHiggins) October 2, 2015" style="color:#fff;" class="twitter-post-link" target="_blank">Twitter Post
After three days of bombing rebel areas, Russia finally hit IS' self-declared capital, Raqqa.
Despite being significantly more technologically advanced than its Syrian counterpart, the Russian air force's bombing campaign appears to be little different to the regime's crude barrel bombing.
"I don't think the Russians exercise the same level of care when it comes to 'collateral damage'," Aymen J al-Tamimi said.
Opposition forces have effectively declared war on Russia, and fired off at least one Grad missile at the Russian-run airbase in Latakia.
Higgins questions the accuracy of these missiles and dismisses rebel claims that opposition groups shot down a Russian Su-25 on Thursday.
"We might also see the rebels getting more support from Arab allies, including more anti-tank guided missiles, which are their most effective weapon and key to many advances. We may even see MANPADS [shoulder-fired surface-to-air missiles] appearing, which would be a significant shift," said Higgins.
Call to arms
Colonel Jameel Salah of the FSA made a plea on Friday for arms from the US to fight off the Russian military.
However, judging by Washington's sheepish response to Russian intervention in Syria, this appears unlikely.
It looks doubtful that the rebels will be given surface-to-air missiles from the US or Europe, for fear they might fall into the hands of the Islamic State group, even as hundreds die in regime air raids.
Arab nations - such as Saudi Arabia, which vocally oppose Russian intervention - might be willing to assist the rebels.
When Saudi Foreign Minister Adel bin Ahmed al-Jubeir was asked by reporters in New York how Riyadh would respond to Russian intervention, his response was simple: "You will see."
"I think the biggest losers have been the West and opposition backers," Tamimi said.
"At this rate, the West's credibility with opposition factions is going to be eroded much further, especially if they start going on Russia's terms for a solution to the crisis."
It would appear that the opposition's Arab allies and Turkey would be far more likely to fill this role.
Despite the Russians' heavy bombardment of rebel areas, Tamimi said the current Russian strategy was to halt the opposition advance on regime areas rather than capture wholesale opposition territory.
The majority of Russian airstrikes has been on rebel pockets in regime areas and bordering opposition territories.
"Containment seems to be the goal here, and then try to have the world accept Assad's survival," he said.
"As for rebel resolve, they may find additional motivations at first in potentially fighting the Russian - but heavy losses from airstrikes could take their toll."
Rebel ranks appear to have been united from the Russian onslaught.
The battle-hardened rebels will in no way be a walkover for the regime and Iranian forces, and have proved a capable fighting force - at least when united.
Opposition groups are also well used to fighting under heavy regime bombing and with short supplies, after four years of fighting.
The myriad of often opposing ideological views of the opposition have often been united in the face of threats, particularly from outside.
The steamroller success of Jaish al-Fatah is one example of how a union of rebel groups - including the Nusra Front - can lead to a remarkable turnaround on the battlefield.
Now, it is not uncommon to see rebel fighters posing for photos with some brandishing al-Qaeda's black standard, and others the green-white-black rebel flag - when they might once be fighting.
"Many of the jihadis seem eager for a fight with Russia, seeing as either 'Muhahideen v Russia in Afghanistan 2.0' or a replay of the battles in the North Caucuses," Tamimi said.
— ISW (@TheStudyofWar) October 2, 2015" style="color:#fff;" class="twitter-post-link" target="_blank">Twitter Post
With hundreds more Iraqi Shia militants and Iranian troops in Syria, Tamimi sees the regime as trying to retake territory in the regime's "rump state" fringes, making Latakia province easier to defend.
There are also reports from Russian media that pro-Moscow Chechens could take part in operations.
Posters from the Islamic State group were circulated on Friday, telling residents under its control that Friday prayers were cancelled due to the bombing.
The extremist group also launched a new offensive on regime enclaves in the eastern city of Deir Az-Zour - largely already held by IS - and a nearby military airport.
Meanwhile, a regime army column is said to be on its way to relieve an IS-surrounded airbase in Aleppo province, reportedly seven kilometres from Kweres.
A pro-regime Facebook page, however, has said that the offensive on the camp had not yet been launched.
In Aleppo, fighting and shelling continued between rebel and regime troops. Kurdish militants cemented their control of the Sheikh Maqsoud province, after opposition al-Nusra Front allies withdrew.
In September, more than 4,100 people died in Syria, according to the Syrian Observatory for Human Rights.
With Russian aircraft launching a heavy bombing campaign of rebel territories, it is feared that the number of dead in October could be much higher.