ISLAMIC State (Isis) militants killed a second captive Lebanese solider at the weekend.

Abbas Medlej’s mother confirmed yesterday that pictures posted by the Islamist group on Saturday showed her son before and after he was beheaded.

“My son was sacrificed,” said Zeinab Noun, clutching a passport-sized photo of him.

A spokesman for Lebanon’s military said it was still investigating the incident.

About two dozen more members of Lebanon’s security forces were seized last month when several Syrian rebel factions, including Isis and the al-Qaida-linked Nusra Front overran the Lebanese border town of Arsal, killing and kidnapping soldiers and policemen in the most serious spillover yet of the neighbouring civil war.

Isis was thought to be holding about 10 of the captives. The group released photos after claiming it had beheaded soldier Ali Sayid late last month.

The militants had earlier released a video showing Mr Sayid claiming he had defected to Isis, though it was suspected he did this under duress.

No reason was given for the first soldier’s execution, but Isis supporters said Mr Medlej was killed after trying to escape.

Local media had reported that negotiations were underway, with the militants demanding cash and the release of Islamists being held in Lebanese detention.

Mr Medlej hailed from a large Shi’ite clan from the eastern city of Baalbak.

His mother vowed revenge on the rival Sunni “apostates.”

But Lebanon has many religious sects. Mr Sayid was a Sunni and Christians are also among those held by Sunni Isis.

Families of the hostages have blocked roads and held demonstrations to push the government to take more action to release the men.

As anger grows over the beheadings there are also fears for the safety of 1 million Syrian refugees in Lebanon.

Isis declared a new caliphate after seizing vast swathes of territory in Syria and northern and western Iraq in June.

The group reached Lebanon in August when it overran Arsal and operates just across the border in the nearby hills of Syria.