Islamic State group militants killed 10 Syrian troops and pro-government fighters in the former jihadist stronghold of Raqa province, a war monitor said Tuesday, displaying their ability to keep mounting deadly attacks.
Despite losing their last piece of territory in Syria in 2019, the Islamic State has maintained hideouts in the vast Syrian desert from which it has carried out ambushes and hit-and-run attacks.
"IS attacked positions and checkpoints belonging to the regime... setting fire to military vehicles and prefabricated houses," the Syrian Observatory for Human Rights said.
Six soldiers were also wounded in the Monday evening attack, with some in critical condition, said the British-based monitor, which relies on a wide network of sources inside Syria.
Government troops control rural areas in the south and east of Raqa province, while Kurdish fighters control the rest.
The city of Raqa was the centre of the Islamic State group's brutal "caliphate" until Kurdish-led forces backed by the United States ousted them in 2017.
In March 2019, Islamic State lost the last territory it held in Syria to a Kurdish-led counteroffensive backed by a U.S.-led coalition, but jihadist remnants continue to carry out deadly attacks.
Targets have included civilians and Kurdish-led fighters as well as government troops and allied pro-Iranian fighters.
Last week, the jihadists attacked a convoy of oil tankers guarded by the army in the Syrian desert, killing seven people including two civilians.
Last month, Islamic State claimed responsibility for a rare bombing in Damascus that killed at least six people near the capital's Sayyida Zeinab mausoleum, Syria's most visited Shiite pilgrimage site.
The Sunni extremist group's brutal rule was marked by beheadings and mass shootings.
Last week, Islamic State announced the death of its leader Abu al-Hussein al-Husseini al-Qurashi, who it said was killed in clashes in northwestern Syria.
Islamic State has had five leaders since it lost the last remnant of the once sprawling "caliphate" it proclaimed across large swathes of Syria and neighbouring Iraq in 2014.
Four of them were killed, including the group's first "caliph", Abu Bakr al-Baghdadi, who died in a US raid in October 2019.
Civil war first broke out in Syria after President Bashar al-Assad's government crushed peaceful protests in 2011. It has since drawn in foreign powers and global jihadists.
The conflict has killed nearly half a million people and driven half of the country's pre-war population from their homes, with many seeking refuge in neighbouring Turkey.