Islamic State group attacks killed at least 34 pro-government fighters and soldiers in the Syrian desert on Wednesday, a monitor said, in one of the deadliest such assaults this year.
The jihadists launched "simultaneous attacks" at dawn on checkpoints and military positions between Raqa, Homs and Deir Ezzor, said the Syrian Observatory for Human Rights, a Britain-based group with a network of sources on the ground.
It said there had been "34 dead, at least eight of them soldiers" and most of the others from the National Defence Forces, a pro-government militia.
The head of the Observatory, Rami Abdel Rahman, warned the toll could rise, citing an unspecified number of wounded, some in serious condition.
The war monitor said Russian warplanes launched strikes on IS positions in the desert, killing seven jihadists.
IS proclaimed a "caliphate" in June 2014 across swathes of Syria and Iraq and launched a reign of terror.
It was defeated territorially in Syria in 2019 but its remnants continue to carry out deadly hit-and-run attacks and ambushes, particularly from desert hideouts, targeting both pro-government forces and Kurdish-led fighters.
IS was blamed for a string of deadly attacks on government loyalists earlier this year.
- Mayadeen -
In August, 33 Syrian soldiers were killed when IS ambushed their bus in the desert near Mayadeen, in Deir Ezzor province, the Observatory said at the time.
Days earlier, 10 loyalists were killed in an IS attack in Raqa province, the jihadists' former stronghold in Syria, the Observatory reported.
Also in August, the jihadists attacked a convoy of oil tanker trucks guarded by the army in the Syrian desert, killing seven people including two civilians.
The same month, IS announced the death of its leader and named his replacement -- the group's fifth chief -- as Abu Hafs al-Hashimi al-Qurashi.
Syria's war broke out after President Bashar al-Assad's security forces crushed peaceful pro-democracy protests in 2011 and then drew in foreign powers and global jihadists.
The conflict has killed more than 500,000 people and driven half of the country's pre-war population from their homes.
Damascus initially lost control over much of Syria to opposition factions, Kurdish fighters and IS group jihadists.
But the army gradually clawed back territory with support from key ally Iran and Lebanon's Hezbollah group, while Russian intervention since September 2015 turned the tide in the government's favour, and Damascus now controls around two-thirds of the country.