From inside the gay Orlando nightclub, the gunman, Omar Mateen told police negotiators to tell America to stop bombing Syria and Iraq and that was why he was "out here right now."
The conversations shed more light on the possible motivations of Mateen, who killed 49 people and injured 53 in the deadliest mass shooting in modern US history.
In a first call he made to a 911 emergency operator, Mateen said "I pledge allegiance to Abu Bakr al-Baghdadi, may God protect him, on behalf of the Islamic State," referring to the head of Islamic State.
Authorities believe Mateen, a U.S. citizen of Afghan descent, acted alone in the June 12 rampage, with no help from Islamist militant networks. The 29-year-old security guard was killed by police after more than three hours in the club.
The FBI and US State Department released partial transcripts of the four calls with the emergency operator and crisis negotiators earlier on Monday, omitting the shooter's references to the leader of Islamic State, saying they did not want to provide a platform for propaganda.
But they later reversed their decision and released the unredacted version after a wave of criticism from US House of Representative Speaker Paul Ryan, Florida Governor Rick Scott and other political leaders.