Daesh's media network on Monday published a video message purporting to come from its leader Abu Bakr al-Baghdadi in what would be his first appearance since declaring the jihadists' now-defunct "caliphate" five years ago, reports Reuters.
In the 18-minute video from the Al Furqan network, a bearded man with Baghdadi's appearance says the Easter bombings in Sri Lanka were Islamic State's response to losses in its last territorial stronghold of Baghouz in Syria.
The group is engaged in a "battle of attrition" and will seek revenge for jailed and killed militants, he says, calling for militants operating in West Africa to multiply attacks against "Crusader France and its allies".
The authenticity and date of the recording could not be independently verified.
The video would be the first from Baghdadi since he was filmed in the Iraqi city of Mosul in 2014. More recent speeches have been released as audio recordings.
Written script at the start of the video dates it to earlier in April, and he can be seen sitting cross-legged on the floor giving an address to several aides with their faces covered.
The speaker looks like a slightly older version of Baghdadi than when he was pictured in 2014, addressing followers from a pulpit to declare a caliphate stretching across Iraq and Syria.
In the footage released on Monday, he is dressed in black robes and a beige waistcoat, with a long greying beard dyed red at the bottom.
Baghdadi's whereabouts have been unknown since Islamic State's territorial control began disintegrating with the fall of Mosul and Raqqa, its strongholds in Iraq and Syria respectively, in 2017.
There had been conflicting reports over whether Baghdadi, an Iraqi, is still alive. But security sources have recently said he is thought to be hiding out in remote areas of Syria or Iraq.
The CIA had no immediate comment on the video.
US air-strikes killed most of Baghdadi's top lieutenants, including "war minister" Abu Omar al-Shishani, "governor of the Iraqi region" Abu Muslim al-Turkmani, group spokesman Abu Mohammed al-Adnani and "governor for Syria" Abu Ali al-Anbari.
Though it lost its last significant territory, the Syrian village of Baghouz, last month, the group has sleeper cells around the world and some fighters operate from the shadows in Syria's desert and Iraq's cities.
It claimed responsibility for the Easter Sunday bombings in Sri Lanka that killed more than 250 people.