BEIRUT (Reuters) – Lebanon has identified the bodies of six of its soldiers found along the Syrian border in an area held by Islamic State until three days ago, sources in the president’s office said.

The Lebanese army launched an offensive this month which ended with Islamic State militants leaving their last foothold along the border on Sunday.

Since then the army has found 10 bodies in the area. DNA tests confirmed that six of those belonged to Lebanese soldiers, the sources and local media reported on Wednesday.

Islamic State militants had for years held territory along the border, and captured 10 Lebanese soldiers in 2014 when they briefly overran the town of Arsal, one of the worst spillovers of the Syrian conflict into Lebanon.

The militants and their families left the border area on Sunday under a ceasefire deal.

The agreement included IS militants identifying where they had buried the soldiers’ bodies, Lebanese army chief General Joseph Aoun said on Wednesday.

“I had two choices: either I continue the battle and not know the soldiers’ fate, or I submit to the situation and find out. Their souls are my responsibility,” he told reporters.

It was not immediately clear if all six belonged to those captured in 2014, however – one of the bodies discovered is believed to belong to a soldier killed in the recent fighting.

Of the 10 captured in 2014, one was killed shortly after and footage of his execution was published by the militants.

Another is believed to have joined Islamic State. His whereabouts is unknown.

(Reporting by Sarah Dadouch; Editing by John Davison and Raissa Kasolowsky)