In the ridges and plains of the Syrian-Lebanese border, tension is simmering between the government in Damascus and Hezbollah, posing risks for stability in Syria as the US-Israeli war on Iran rages.
Damascus deployed thousands of troops along its side of the border at the February 28 onset of the war, in what the government described as a defensive move aimed at countering smuggling, infiltration attempts and "security gaps".
On Tuesday, it accused the Shiite, pro-Iranian Hezbollah of shelling military targets near the Syrian town of Sarghaya, in the foothills of the Anti-Lebanon Mountains separating the two countries. The accusation came as Hezbollah said it battled Israeli troops who came into Lebanon from that direction. Israel said it had no knowledge of the clashes.
The day after, French President Emmanuel Macron called Lebanese President Joseph Aoun and Syrian President Ahmad Al Shara to discuss "the security escalation", the Lebanese Presidency said, without elaborating.
A security source in the region said that Israeli commandos might have used Syrian territory to attack Hezbollah from the rear. The Syrian military "lacks the capacity, and the desire" to stop such moves, considering Hezbollah had fought alongside the former regime during the country's civil war.
Some of Syria’s best troops, the source said, have been deployed to the Qusair region further north, which acted as a backup centre for Hezbollah during the past decade before Assad's ouster.
Among them are 800 mostly Uighur elite fighters, who had comprised Mr Al Shara’s shock troops in the civil war and were later incorporated in the new armed forces, who are mostly Sunni, the majority religious denomination in Syria. These fighters are seen as "incorruptible", and they will efficiently carry Mr Al Shara's orders to stop any weapon smuggling. However, the president gave them orders to secure the frontier "tightly but without any provocation that could lead to war," the source said.
Mr Al Shara led Hayat Tahrir Al Sham (HTS), a splinter group from Al Qaeda. After he was declared president in January last year, he moderated his rhetoric and became friendly with Washington. He has also not ruled out peace with Israel.
A post-Assad diplomatic drive improved Syria's ties with most Arab countries, except Lebanon. The two countries share a 375-kilometre border that was not delineated since the two countries were carved out of the remnants of the Ottoman Empire in 1920.
Qusair is situated across the border from Hermel in Lebanon, which is believed to house Hezbollah weapon stores. Parts of Lebanon's Bekaa valley, between Beirut and central Syria, are under de facto Hezbollah control. On March 1, Hezbollah entered the Iran war by launching rockets at Israel in response to the attack that killed Supreme Leader Ali Khamenei. Hezbollah followed the religious path set by the late Ayatollah.
The troops in Qusair are "itching to go into Hermel and settle scores with Hezbollah", especially if Israel provides air support for what could become a Syrian buffer zone inside Lebanon. "Hermel in this case would fall not in days, but in hours," the source said. The group no longer has a base in Syria, unlike during other Hezbollah-Israel wars in the past three decades.
However, Mr Al Shara realises that France and other European powers would be against any incursion into Lebanon, which they are trying to help recover from its deepening economic and political crises. "Macron told Al Shara as much during the call," the source said. The Syrian civil war, from 2011 to 2024, has also left Syria "on its knees," and the country cannot afford what could become a long war of attrition with Hezbollah.
Relations between Syria and Lebanon have often been acrimonious since they both gained independence from France in the 1940s. Lebanon fell under Syrian tutelage from 1990 to 2005. Syria, under Assad family rule, played a big role in the creation of Hezbollah in the 1980s and later became a backup command and logistics centre for the group, as well as offering a supply route from Iran.
However, the Sunni rebels that Hezbollah fought on behalf of the former president, Bashar Al Assad, are now in power in Damascus. Since his ouster in December 2024, some gangs have continued the smuggling of weapons to the group, according to the new government.
A Syrian figure who is well connected with Mr Al Shara's inner circle of former HTS operatives, said that a scenario under which he could abandon his caution cannot be ruled out. The president could send troops into the Bekaa, or across the Anti-Lebanon Mountains to take Hezbollah strongholds.
“The alliance with America is his main foreign policy motivator,” he said. "If America says go in, he will".
