Abu Mohammad al-Adnani

The Russian Foreign Ministry has said it is "highly likely" that Abu Bakr al-Baghdadi, the leader of Islamic State (IS, former ISIS/ISIL), was eliminated in an airstrike carried out by the Russian Air Force in Syria earlier in May.

The leader of Islamic State, Abu Bakr al-Baghdadi, has expressed confidence in victory as Iraqi forces entered the city of Mosul where he declared a “caliphate” two years ago.

The Pentagon said on Sept. 16 that a U.S.-led coalition airstrike on Sept. 7 killed an Islamic State of Iraq and the Levant (ISIL) leader who oversaw the extremist militant group's propaganda.

Pentagon spokesman Peter Cook said that the airstrike took place near Raqqa and targeted and killed Wa'il Adil Hasan Salman al-Fayad, also known as Dr. Wa'il.

The Islamic State of Iraq and the Levant (ISIL) called on Muslims on Oct. 13 to wage jihad on Russia and the United States, as Moscow announced it had intensified its air campaign against Islamic militants in Syria.

The Islamic State of Iraq and Syria (ISIS) group’s spokesman Abu Mohamed al-Adnini confirmed on Tuesday the killing of the militant organization’s second in command in the U.S. air strike earlier this year.

Islamic State (IS) has reportedly accepted a pledge of allegiance from the Nigerian insurgent movement Boko Haram.

The acceptance of the allegiance was made in an audio recording, which was posted on IS-related websites on Thursday, Al Jazeera reports.