"We announce, relying on God, a blessed campaign to take revenge" over the death of Abu Ibrahim al-Qurashi and the group's former spokesman, an audio message attributed to the group and circulated on the Telegram messaging app said.

The group's new spokesman, Abu-Omar al-Muhajjir, also called on supporters to resume attacks in Europe, taking advantage of the "available opportunity" of "the crusaders fighting each other" -- in reference to Russia's invasion of Ukraine.

The militant group's previous leader died in early February when he detonated a bomb to avoid capture during a US raid in northwest Syria, the White House and US defence officials said.

On March 10, the group confirmed his death, along with the group's former spokesman, naming Abu Hasan al-Hashemi al-Qurashi as the new leader.

Little is known about the new leader, who is the jihadist group's third chief since its inception.

After losing their last territory under a military onslaught backed by the US-led coalition in March 2019, the remnants of IS in Syria mostly went into desert hideouts.

They have used such hideouts to ambush Kurdish-led forces and Syrian government troops. The jihadists also continue to mount attacks in Iraq.