Russia's military intervention in the Syrian war has all but destroyed a deal agreed last month to halt fighting between warring sides in the town of Zabadani near Lebanon's border, unpicking a rare success for foreign-backed diplomacy in the 4-year-old conflict. The deal also applied to two villages in the northwestern province of Idlib. Implementation of the deal agreed with U.N. help to extricate rebels from Zabadani and trapped villagers from al-Foua and Kefraya has effectively been shelved following Russian airstrikes in support of President Bashar Assad, three sources familiar with the talks told Reuters. Syrian troops backed by Hezbollah have taken most of Zabadani in an offensive they launched starting July, squeezing rebels in around 1-square kilometer in the town. While local cease-fires in both locations continue to hold, this means it may be only a matter of time before fighting there resumes between insurgent groups on the one hand, and the Syrian military and its Lebanese ally Hezbollah on the other. The rebels, including the Sunni Islamist group Ahrar al-Sham and the Al-Qaeda-linked Nusra Front, had been waging a parallel attack on Kefraya and al-Foua, two Shiite villages in the northwestern province of Idlib. The bleak outlook for the deal fits into a broader picture of escalation, as deepening foreign involvement further complicates a conflict that has already killed 250,000 people and shattered a nation. "There's a cease-fire now but that's about it. The deal has become another victim of the Russian escalation. People have forgotten about implementation," said a person with knowledge of the negotiations. Meanwhile, two senior regional officials with knowledge of military and political developments in Syria and close to its government said a ground offensive by the Syrian army and its allies, backed by Russian airstrikes had rendered the agreement irrelevant. "The agreement has fallen. Kefraya and Al-Foua are out of the race. The Russian-Iranian alliance is determined to liberate Idlib. And thus Kefraya and Al-Foua... will fall on the way," said one of the officials, who has close ties to Damascus. The other senior official said: "The attack that started in the Hama countryside in the direction of Idlib will certainly lead to the liberation of Kefraya and Al-Foua and thereby negating the real reason of the agreement." Their comments point to increased confidence on the side of the Syrian government and its allies and their belief in the possibility of a military victory over insurgents in western Syria, the main focus of Russia's airstrikes. An official from Ahrar al-Sham said that the group was currently not commenting to the media about the agreement. But the rebels are hoping Russia's intervention will lead to increased military support from their own foreign backers, particularly Sunni Saudi Arabia, which is locked in a struggle for influence across the region with Shiite Iran. Backed by Russian airstrikes, the Syrian army and allies including Hezbollah this week launched new ground offensives against insurgents in two strategically important areas of Hama province this week. The Syrian Observatory for Human Rights, a Britain-based organization that tracks the war using sources on the ground, said Friday they had yet to make significant territorial gains in those areas. The success of the U.N.-backed negotiations had offered a rare ray of hope in the war where diplomacy has mostly made no headway. Iran had negotiated on behalf of the Syrian government and Hezbollah. Ahrar al-Sham, one of the most powerful rebel groups in Syria, had secured a mandate to negotiate on behalf of a range of insurgent groups. The talks took place in Turkey, one of the states that supports the insurgents fighting Assad. The United Nations said on Oct. 2 it had been forced to suspend planned humanitarian operations in Syria under the ceasefire agreement due to "a surge of military activity." Initial steps had included evacuations of wounded. The office of U.N. envoy for Syria Staffan de Mistura at the time called on the parties to fulfil their responsibilities and to reach necessary understandings to implement the agreement.