Beirut, Asharq Al-Awsat—The Al-Qaeda-affiliated Al-Nusra Front on Friday killed one of the 22 Lebanese soldiers it captured last month, threatening to kill another unless Beirut ends Hezbollah’s involvement in the Syrian conflict.

A Twitter account affiliated to the Al-Nusra Front, a Sunni radical group in Syria, said the Lebanese soldier had become “the first victim of the intransigence of the Lebanese army which has become a plaything in the hands of the Iranian party,” referring to the Shi’ite Hezbollah militia.

Syria’s mostly-Islamist rebels accuse the Lebanese army of facilitating Hezbollah’s movement into Syria where the militia has been instrumental in fighting alongside forces loyal to President Bashar Al-Assad.

Last month Sunni militants, including fighters from the Islamic State of Iraq and Syria (ISIS), crossed the border from Syria into Lebanon and captured at least 22 Lebanese soldiers. Al-Nusra Front have demanded the release of Sunni prisoners held in Lebanese jails in exchange for the release of the Lebanese soldiers.

The latest incident increases pressures on Qatar which has been mediating the release of the soldiers.

Al-Nusra Front broadcast a video of the execution, including footage of a second Lebanese soldier which it has threatened to kill. With his arms bound and speaking following the execution, the Lebanese soldier said: “If you don’t stop attacking and inciting against our Sunni brethren then I will follow my fellow soldier who was killed right there”

He called on “the party of the devil,” Hezbollah, to withdraw from Syria and return to fighting Israel.

In other news, at least two Lebanese soldiers were killed and three others injured after a bomb struck a military vehicle in Arsal, the Lebanese military said in a statement.

A few hours after the bombing, the Lebanese military stepped up operations against Islamist militants positioned along the Anti-Lebanon Mountains as Syrian military jets carried out airstrikes, Lebanon’s state-owned National News Agency reported.

Contrary to previous attacks on the town, Friday’s bombing occurred in a residential area, creating confusion in the ranks of the Lebanese military, the deputy mayor of Arsal Ahmad Fliti told Asharq Al-Awsat.

A remote-controlled bomb, weighing around 20 kilograms, left a 60 centimeter-deep crater at the town’s entrance, the Lebanese Broadcasting Corporation International reported.

Fliti ruled out the prospect of a renewed wave of violence in the border town, maintaining that the majority of Islamist rebels have retreated towards the Syrian interior.