BEIRUT/BAGHDAD - The Islamic State group has killed at least 73 Syrian government troops and allied fighters in surprise attacks on their positions in a desert region, a monitor said on Friday.

The deaths came in Thursday attacks launched as the militant group faces a Russian-backed regime offensive against some of its last bastions.

The extremist group claimed the attacks against several positions south of the town of Sukhna in central Homs province, saying its fighters had killed dozens of regime troops.

The attacks come a day after IS released what it said was an audio recording of its leader Abu Bakr al-Baghdadi, the first in a year, in which he urged resistance.

Syrian troops pushed through the vast desert that separates the main cities of the west from the Euphrates Valley this summer and broke an IS siege of nearly three years on government enclaves in the eastern city of Deir Ezzor earlier this month.

Thursday’s attacks targeted government forces around Deir Ezzor and on their supply lines through the Sukhna area from the west, the Observatory said.

“The first attacks were carried out against checkpoints manned by loyalist troops in Al-Shula,” a village near Deir Ezzor, the Britain-based monitoring group said.

“IS then carried out a series of attacks against checkpoints along the length of the motorway from Al-Shula to south of Sukhna.”

Syrian state media made no mention of the army’s losses, but said its troops “confronted an attack by the terrorist Daesh group on the highway between Deir Ezzor and Palmyra, deep in the Badia desert.”

State news agency SANA said the army had “inflicted heavy losses on the ranks of the terrorists”, adding that units were “currently working to clear remaining Daesh terrorists from the area and secure the highway for traffic”.

The Observatory said at least 45 IS fighters had been killed in the fighting.

The attacks by the militants came as they face multiple offensives against the last bastions of their self-proclaimed caliphate.

In addition to the Russian-backed government offensive, a US-backed alliance of Kurdish and Arab fighters is battling the group, which is also under attack in neighbouring Iraq.

Iraq forces launch attack on

IS-held town of Hawija

Iraqi forces on Friday launched an assault on the northern town of Hawija, one of the last bastions in the country still held by the Islamic State group, which is also under attack in neighbouring Syria.

The operation came after IS released what it said was an audio recording of its leader Abu Bakr al-Baghdadi urging resistance, the first such intervention in nearly a year.

“The leaders of the Islamic State and its soldiers have realised that the path to... victory is to be patient and resist the infidels whatever their alliances,” said the voice in the recording, whose authenticity Washington said it had “no reason to doubt”.

Since Baghdadi’s previous message to his followers last November, the territory the militants still hold in the cross-border caliphate they proclaimed in 2014 has shrunk to a fraction of its former extent.

“A huge military operation has begun to liberate Hawija and its surrounding areas,” the operation’s commander, Lieutenant General Abdel Amir Yarallah, said in a statement.

Iraqi forces launched an offensive to retake the militant enclave around Hawija on September 21, swiftly taking the town of Sharqat on its second day before pushing on towards Hawija itself.

Yarallah said that Friday’s assault marked the second phase of the operation and aimed to recapture Hawija and the towns of Al-Abbasi, Riyadh and Rashad to its west, east and south.

All are mainly Sunni Arab towns that have long been bastions of insurgency and were bypassed by government forces in their push north on second city Mosul last year which culminated in the militants’ defeat in their most emblematic stronghold this July.

Yarallah said that troops were now advancing on the town of Al-Abbasi.

He said the operation involved the army, the federal police, counterterrorism units and the Rapid Intervention Force, as well as tribal volunteers and the paramilitary Popular Mobilisation force, mainly made up of Iran-trained Shiite militia.

The enclave lies east of the Tigris River and south of one of its major tributaries, the Little Zab, and troops erected pontoon bridges during the night to enable the assault to begin, Yarallah said.

The Popular Mobilisation force said that IS had set fire to two oil wells in the Alas field, southeast of Hawija, in a bid to provide cover and slow the advance of loyalists forces.

Prime Minister Haider al-Abadi hailed the second phase of the operation to recapture the area.

“As we promised the sons of our country, we are going to liberate every inch of Iraqi land and crush the Daesh (IS) terrorist gangs,” Abadi said.

“We are on the verge of a new victory to liberate the residents of these areas from those criminals.”

The Hawija enclave is one of just two areas of Iraq still held by IS, along with a stretch of the Euphrates Valley near the Syrian border which is under attack too.

Further up the Euphrates Valley on the Syrian side of the border, IS is facing rival offensives by US-backed fighters and Russian-backed government forces.

The militants launched a major counteroffensive against government forces on Thursday, killing 58 troops and militia in a series of attacks along their supply lines, the Syrian Observatory for Human Rights said.

Most of the dead came near the desert town of Sukna, on the main highway between the big cities of the west and Euphrates Valley city of Deir Ezzor, the Britain-based monitoring group said.

Syrian troops pushed through the desert and broke a three-year IS siege of government enclaves in Deir Ezzor earlier this month. They are now battling to retake the rest of it.

Further upstream, a US-backed alliance of Kurdish and Arab fighters is poised to capture the onetime IS bastion of Raqa, once a byword for militant atrocities.

A top US-led coalition commander told AFP on Thursday that the militants were now breathing their “last gasps” in the city.

He said the coalition was already setting its sights on another IS-held town in the Euphrates Valley - Al-Mayadeen, between Deir Ezzor and the Iraqi border.