BEIRUT - Syria's al Qaeda offshoot Nusra said on Friday it killed a captive Lebanese soldier in retaliation for the arrest by Lebanese authorities of women identified as wives of Islamist militants.
The soldier was one of more than two dozen members of the security forces taken captive by militants affiliated to the Nusra Front and Islamic State when they staged an attack on the Lebanese border town of Arsal in August.
Lebanese authorities earlier this week said they had detained a wife of Islamic State leader Abu Bakr al-Baghdadi and the wife of a Nusra front leader..
The women were apparently viewed by some Lebanese security elements as a possible bargaining chip with the militants to gain the release of the captive soldiers.
Nusra warned in the statement they would execute another prisoner among the captive soldiers "within a short period" if the Lebanese authorities did not release the women captives.
Spillover from the Syrian conflict has repeatedly jolted neighbouring Lebanon.
Militants affiliated to the al Qaeda-linked Nusra Front and Islamic State are demanding the release of Islamists held by the Lebanese authorities in exchange for the captured members of the Lebanese security forces.
The soldier is the fourth killed by the militants since August in an attempt to put pressure on Lebanese authorities to accept a prisoner swap.
Last Tuesday, at least six Lebanese soldiers were killed by gunmen from Syria who attacked an army patrol near the border.
Shortly after the execution of Ali al-Bazzal was announced, protesters blocked a highway near his home village of Bazalia not far from Arsal. Armed men also appeared in the streets there, security sources said.
Many Sunni Syrian rebels and hardline Lebanese Sunni Islamists accuse Lebanon's army of working with the Lebanese Shi'ite movement Hezbollah, which has sent fighters to aid Syrian President Bashar al-Assad, a member of the Shi'ite-derived Alawite minority.
Islamic State has declared a caliphate and seized wide areas of Iraq and Syria, Lebanon's neighbour to the east.
The Lebanese security forces have cracked down on the group's sympathizers and the intelligence services have been extra vigilant on the borders with Syria.