U.S. President Donald Trump hailed slain conservative activist Charlie Kirk as a "martyr for American freedom" on Sunday and vowed at his memorial service to carry on his work, while again accusing what he called the "radical left" for Kirk's murder.

"The violence comes largely from the left," Trump said without citing any evidence, in remarks that downplayed political violence from the right and often turned starkly partisan in contrast to the more solemn tone that most other speakers adopted.

Trump has been blaming the left for the deadly shooting before a suspect was even detained. His messaging reflected the dual nature of Kirk's memorial, which had the feel of a religious revival mixed with a "Make America Great Again" rally.