Two weeks after the Islamic State group confirmed that its spokesperson Abu Muhammad al-Adnani had died in an airstrike, the United States and Russia appeared to spar over who killed him. The Pentagon on Monday said the strike was carried out by US forces, but on August 31, Russia had claimed responsibility for eliminating the militant.

According to the Washington Post, Pentagon officials called Russia’s claims "a joke". The Kremlin countered this by saying such words were all the US “can say to justify their unawareness". The sniping comes days after the two major powers signed a ceasefire agreement in Syria. The two countries are backing opposing groups in the Syrian civil war, but both have been claiming to go after the Islamic State. The “cessation of hostilities” came into effect early Tuesday, as the country observed Eid al-Adha. Light shelling was reported from parts of the country, but rights groups said that conflict zones on the whole were quiet, Al Jazeera reported.

The Islamic State had on August 31 confirmed al-Adnani’s death, saying he had been in charge of external operations, including major attacks in Europe. The Islamic State-linked Amaq news agency said Adnani was "martyred while surveying the operations to repel the military campaigns against Aleppo". The Barack Obama government had designated Adnani a "global terrorist" earlier in 2016, and put a reward of $5 million on his head (approximately Rs 33 crore).