BAGHDAD — Iraqi government officials said Sunday that Russian experts had arrived in Iraq to help the army get 12 new Russian warplanes into the fight against Sunni extremists, while the extremists declared their leader the caliph, or absolute ruler, of all jihadi organizations worldwide.

The Russian move was at least an implicit rebuke to the United States, which the Iraqis believe has been too slow to supply American F-16s and attack helicopters — although the United States is now in the process of providing both.

“In the coming three or four days the aircraft will be in service to support our forces in the fight” against the insurgents of the Islamic State in Iraq and Syria, said Gen. Anwar Hama Ameen, the commander of the Iraqi Air Force, referring to five SU-25 aircraft that were flown into Iraq aboard Russian cargo planes Saturday night, and two more expected later Sunday.

Also on Sunday, the Islamic State in Iraq and Syria released a 34-minute audio recording of a speech by its official spokesman, Abu Muhammad al-Adnani, who said that the insurgency’s leader, Abu Bakr al-Baghdadi, was now the world’s caliph and as such had declared all other jihadi organizations void and under his direct control, according to the SITE Intelligence Group, which monitors extremists’ online presence.