BEIRUT - The Islamic State jihadist group has executed one of dozens of Druze hostages abducted from Syria's southern province of Sweida last week, a journalist in the area and a monitor said Sunday.

IS went on a rampage in Sweida on July 25, killing more than 250 people - mostly civilians - in the deadliest attack ever to target the mostly government-held province and its Druze religious minority.

The jihadists also kidnapped more than 30 people, most of them women and children, from a village in the province, which had previously remained largely isolated from Syria's seven-year civil war.

On Thursday, IS killed a 19-year-old male student who was among the hostages, the head of the Sweida24 news website Nour Radwan told AFP.

Quoting relatives, Radwan, who was speaking from Sweida, said the young man was taken from the village of Al-Shabki on July 25 along with his mother.

His family received two videos, the first showing him being decapitated and the second of him speaking before being killed as well as images of his body after his death, Radwan said.

Sweida24 posted online part of a second video, which was seen by AFP, showing a bearded young man who appeared to be sitting on the ground in a landscape of grey rocks.

He is wearing a black T-shirt and tracksuit bottoms, and his hands are tied behind his back.

The video could not be independently verified.

IS has not claimed the kidnappings and did not publish the video on its usual channels.

IS jihadists have lost much of the territory they once controlled in Syria after overrunning large swathes of it in 2014, but they retain a presence in the east of the country and in the vast Badiya desert that sweeps through its south.

The regime has been fighting in recent weeks to expel IS fighters from a patch in the neighbouring province of Daraa.

The Syrian Observatory for Human Rights, a Britain-based war monitor, said the young man's execution was the first since the kidnappings.

The execution came "after the failure of talks between IS and regime forces over the transfer of IS fighters from the southwest of Daraa province to the Badiya" desert, said the Observatory.

Head of Syrian regime

research centre killed

The head of a Syrian government research centre fabricating weapons has been killed in an explosion targeting his car, a Britain-based monitor said Sunday.

The pro-regime Al-Watan newspaper confirmed the killing.

General Aziz Asbar was killed late Saturday along with his driver in the central province of Hama, the Syrian Observatory for Human Rights monitor said.

Asbar headed the research centre in Hama's Masyaf, which was targeted in Israeli air strikes last month and in September last year, the Britain-based Observatory said.

According to the United States sarin gas was being developed at the centre, a claim denied by Syrian authorities who say the country does not possess any chemical weapons after a 2013 agreement to hand over its chemical arsenal.

Observatory head Rami Abdel Rahman said that experts from regime ally Iran were present at the Masyaf centre, which was developing short-range surface-to-surface missiles.

"The general was close to Syrian President Bashar al-Assad and to Iran," the monitor said.