The troops of the Syrian regime is now threatening to totally besieged rebel neighborhoods in Aleppo, the second largest city, after having managed to cut their main supply route.

This advance was the largest since the outbreak of fighting in Aleppo in 2012 and also is the main victory of the regime of Bashar al-Assad since Russia launched its air campaign in Syria in September.

These developments coincide with the military fiasco of diplomatic efforts as new peace talks in Geneva were suspended until February 25. They threaten parallel exacerbate the humanitarian crisis in Syria. Nearly 40,000 civilians have fled since the beginning of the offensive on Aleppo earlier this week, reported Thursday the Syrian Observatory for Human Rights (OSDH).

Government forces are now closer than ever to fully besiege the rebels who control the eastern neighborhoods of the former economic capital of the country since 2012.

Three days after starting their major offensive, they have managed to break the siege imposed Wednesday by the rebels since 2012 in two Shiite towns in the province, and Nebbol Zahra. This victory allows them to cut the main supply route insurgents with Turkey.

Aleppo rebels and risk being completely besieged, said the director of OSDH, which has a wide network of sources across Syria. “Unless they receive emergency aid from the Gulf and Turkey, it could mark the beginning of the end for them,” he told AFP Rami Abdel Rahman, director of the OSDH. “With the loss of this axis, the only remaining supply route is long and complicated and will be the next target” of the plan, he added, in reference to the road called Castello, northwest of the city. “If the rebels lose, the seat will be total,” said Abdel Rahman.

‘Major breakthrough’

He said at least 5,000 Nebbol of Shiite militiamen and Zahra could join the Syrian army, which now has good morale after Wednesday’s win. “The regime has been in 72 hours a victory that eluded him over the last three years,” stressed Mr. Abdel Rahman. He received it for hundreds of strikes carried out by Russian planes against rebel positions.

A Nebbol Zahra and his troops were welcomed by a cheering crowd threw rice and flowers in celebration, according to Syrian state media. The chain of Hezbollah Al-Manar also showed the crowd and soldiers waving the Syrian flag and that of the Lebanese Shiite movement which fights alongside the army of Bashar al-Assad. “God, Syria, Bashar, that’s all,” they chanted.

Nearly 100 rebels and 64 pro-regime fighters have been killed since the offensive began Monday after the OSDH. The insurgents, including Islamists and fighters of the Al-Nusra Front (branch of Al-Qaeda in Syria) “suffer from a lack of weapons and ammunition.”

For experts Faysal Itani and Hossam AbouZahr the Atlantic Council, the progress of the plan is a “hard blow” to the rebels and shows how the Russian intervention has changed the game for power in Damascus. “Compared with its setbacks there just five months, the regime is now well placed to divide, isolate and move on opposition positions in several key areas,” they wrote on the website of the Atlantic Council.

This is a “major breakthrough” for the regime, added Karim Bitar, from the Institute of International and Strategic Relations. It “could be the final stage of a plan that began with the Russian intervention. Control of Assad on Syria helpful + the + is no longer threatened, “said the expert.

In London, US Secretary of State John Kerry has again claimed Thursday arrest of Russian bombing in Syria, accusing Moscow implicitly to have torpedoed the Geneva peace talks.