APRNEWS - A string of Islamic State group suicide attacks in southern Syria has killed at least 40 people, mostly pro-regime fighters, in one of the jihadists' deadliest assaults in months, a monitor said Wednesday.

The Syrian Observatory for Human Rights said the blasts hit several areas of the largely government-held southern province of Sweida, where IS retains a presence in a northeastern desert region.

The attacks came almost a week into a deadly Russia-backed regime campaign to oust IS fighters from a holdout in a neighbouring province of the country's south.

"Three bombers with explosive belts targeted Sweida city alone, while the other blasts hit villages to the north and east," the Observatory said. Later on, a fourth suicide attack hit the city.

Rami Abdel Rahman, the head of the Britain-based Observatory, said the jihadists then followed up with further attacks, seizing three of the seven villages they had targeted.

He said 26 pro-government fighters had been killed and more than 30 people wounded in the assault on populated areas close to Sweida city.

Syria's official news agency SANA confirmed the attacks had killed and wounded people in the provincial capital.

State television also reported casualties in villages to the north and east, adding that the army was targeting IS positions in Sweida province's eastern countryside.

- Abandoned shoes -

SANA published images of the aftermath of the attack in Sweida city.

The remains of a victim lay sprawled on a staircase near a damaged wall, while abandoned shoes lay in the middle of the road among fruit that had spilled out of cartons.

Abdel Rahman said unidentified warplanes were also targeting IS fighters in the area.

Despite pro-government forces ousting the group from urban centres in eastern Syria last year, surprise IS raids in recent months have killed dozens of regime and allied fighters.

The regime of President Bashar al-Assad has in recent weeks ousted rebels from a majority of the country's south, part of which borders the Israeli-occupied Golan Heights.

His forces are now closing in on a patch of territory in nearby Daraa province held by jihadist group Jaish Khaled bin al-Walid, which has pledged allegiance to IS.

The group, which has around 1,000 fighters in the region, has been the target of an intense campaign of bombing by Russian and Syrian jets in recent days.

SANA said the attacks in Sweida "aimed at diminishing the military pressure... on IS remnants facing their inevitable end in the western Daraa countryside".

- Desert holdouts -

A Syrian military source accused Israel on Tuesday of firing at one of its warplanes as it carried out operations against jihadists in southern Syria.

Israel's army earlier said it had shot down a Syrian fighter jet that had infiltrated Israeli airspace, risking another escalation in the sensitive border zone.

The Damascus regime has long accused Israel of backing IS and other opposition factions.

Clashes raged Tuesday between regime troops and IS jihadists on the northern edges of the border town of Saida, the Observatory said.

SANA later said "army units blocked an IS attack on a number of villages in northeastern Sweida, killing a large number" of the jihadists.

IS overran large parts of Syria and neighbouring Iraq in 2014, declaring a self-styled "caliphate" in territory it held.

The jihadists have since been ousted from all major urban centres in both countries, but they retain a presence including in desert border areas.

In Syria, IS controls a pocket of the eastern province of Deir Ezzor on the Iraqi border, and is present in parts of the vast central Badiya desert including in Sweida.

More than 350,000 people have been killed and millions displaced since Syria's war started in 2011 with the brutal repression of anti-government protests.

By AFP