SWAT police officers respond after a gunman opened fire at the Tree of Life synagogue in Pittsburgh, Pennsylvania, US, October 27, 2018. (Photo: John Altdorfer/Reuters)

US President Donald Trump denounced the mass murder, ordering flags to be flown at half-staff through Wednesday as a mark of solemn respect for the victims.

UN Secretary General Antonio Guterres called for a united front to roll back the forces of racism, anti-Semitism, Islamophobia, and other forms of hatred, bigotry, discrimination and xenophobia gaining strength in many parts of the world. German Chancellor Angela Merkel likewise called the attack an act of blind anti-Semitic hatred. French President Emmanuel Macron strongly condemned the attack while Canada's Prime Minister Justin Trudeau offered solidarity with the victims.

The shooter was identified as a 46-year-old local resident named Robert Bowers. Taken into custody after a firefight with police, the suspect was transferred to hospital. US prosecutors later Saturday charged him with 29 counts of federal crimes of violence and firearms offenses, including 11 counts of using a firearm to commit murder and 11 counts of obstructing the exercise of religion resulting in death.