ORLANDO, Fla. — Islamic State has now claimed responsibility for the deadly massacre at the Pulse nightclub in Orlando, Florida, Reuters reported.

The announcement came hours after lawmakers claimed that shooter Omar Mateen, 27, called 911 and pledged allegiance to ISIS before opening fire inside the club.

>>Read the latest on the Orlando shootings

A woman who lives next door to Mateen told WFTV's Jamie Holmes that their nearby apartment was evacuated Sunday morning while the FBI entered Mateen's home.

Authorities are asking anyone who knew Mateen to please come forward.

Mateen was reportedly known to law enforcement, but was not the target of an investigation.