President Donald Trump and other prominent American political figures are heading to Arizona to speak at a memorial for Charlie Kirk, the 31-year-old conservative activist who was killed two weeks ago, BBC reported.

The event, organised by Turning Point USA (TPUSA), is on Sunday at State Farm Stadium in Glendale and could be attended by more than 100,000 people.

Heightened security is expected, including "TSA-level screening", according to TPUSA.

Kirk, who co-founded Turning Point USA when he was 18, was shot at a speaking event on a Utah university campus on 10 September, reigniting concerns about political violence in the US, according to BBC.