Is Syrian president Bashar Al Assad finally winning? One can feel a deep sense of grief running through opposition factions whether inside or outside Syria over how events have unfolded over the past two weeks.

Pro-regime forces have made a series of major gains in northern, central and southern Syria over the past week.

More strikingly, they broke a three-year siege imposed by the rebels around the Shia towns of Nubbol and Zahraa, 20 kilometres from Aleppo city, which represents a major setback for the rebels especially as it could disrupt a game of encirclement and counter-encirclement that sustained the rebels’ control of much of Aleppo since 2012.

Five months after the regime’s forces seemed incapable of halting the string of victories achieved by the rebels in northern Syria, which led to the Russian military intervention to prop up their ally, the regime appears to be on the offensive. The offensive is seen n northern Latakia, the western Ghouta near Damascus, Deraa and in the rural areas of Hama, Idlib and Aleppo. The regime appears to have made an impressive comeback.

It is hard to judge how one side is doing through such tactical gains. The rebels were clearly on the winning side just a year ago, while the regime’s army suffered from a shortage in manpower, as admitted by Mr Al Assad himself during his last speech in August.

The breaking of the siege of Nubbol and Zahraa last week, as well as the siege of Kweiris airbase near Raqqa in November and the takeover of Sheikh Maskeen in Deraa last month, were spearheaded by foreign militias beholden to Iran.

The opposition’s real crisis is much deeper, hence the state of grieving widely felt by the rebels. These setbacks come amid profound internal, regional and international challenges that could tip the balance dramatically in favour of the regime.

Internally, a considerable number of rank-and-file rebels have been exiting the battlefield. This includes fighters within hardline groups such as Ahrar Al Asham and Jabhat Al Nusra. This trend originates from familiar issues involving dissatisfaction with their commanders, for various reasons, but has been aggravated by the ruthless air campaign that is deepening individuals’ frustrations and gives them a better reason to leave.

This trend was captured on a rare audio message by Abu Mariyyah Al Qahtani, a prominent jihadi leader and one of the founders of Jabhat Al Nusra in Syria. In the message, which was sent out via social media before the regime’s recent gains, he advised defectors to overlook their commanders’ behaviour and return to jihad and consider it as “an act of worship even if they fought on their own”.

Al Qahtani specifically mentioned Ahrar Al Sham and Jabhat Al Nusra in his message. His message is particularly interesting because he is a well-known critic of the conduct of the leaders of such groups, and because such a trend takes place even with supposedly ideological hardliners. References to such trends are commonly made on social media platforms. One member of Jabhat Al Nusra also said: “Whoever abandons jihad because there are many thieves, opportunists, profiteers or because of the lack of credibility within some factions is like a person who abandons prayers because his shoes were stolen on the mosque’s doorsteps.”

Such statements highlight the inability of rebel factions to retain fighters. Fighters who once tolerated division and infighting among the anti-regime forces find it harder to do so as the scale of destruction has increased exponentially since the Russian intervention.

This reflected on the groups that are supposed to be the most powerful in the north, primarily Ahrar Al Sham. Such groups could not stop the regime’s advances and were apparently reduced to their rightful size after they failed to hire or retain such fighters.

Regional backers of the opposition have also scaled down their support, also just before the regime’s advances.

Turkey, Jordan and Saudi Arabia seemed similarly in disarray unable or unwilling to prop up their allies. The fact that Jordan has been closely coordinating with the Russians, through a fledgling nerve centre recently established in the kingdom, has coincided with a noticeable decrease in the flow of aid into southern Syria. The seeming helplessness of countries like Saudi Arabia and Turkey, has led many to conclude that the regime has finally turned the tables.

In this context, western and regional countries find themselves in a situation where the impact of the regime’s campaign on extremist forces in the north aligns with their objective of weakening extremists without necessarily aligning themselves with the regime. The opposition, on the other hand, is losing on that front: even though many rebel forces are nationalists who do not wish to have extremists decide the future of their country, they are either weak or coordinate with extremist groups.

The rebels’ setbacks are undoubtedly among the worst in four years. But what make them particularly alarming is how the internal, regional and international attitudes seem to be turning against them.

Hassan Hassan is a resident fellow at the Tahrir Institute for Middle East Policy, a think tank in Washington, DC, and co-author of ISIS: Inside the Army of Terror

On Twitter: @ hxhassan