Trump calls NY shooting 'senseless' violence by 'crazed lunatic'

US President Donald Trump on Tuesday called a mass shooting in New York a "senseless act of violence" carried out by a "lunatic."

Trump posted on social media that he had been briefed on late Monday's incident, in which a gunman shot four people, then apparently took his own life, in a Manhattan skyscraper.

One of those killed was a police officer.

"I trust our Law Enforcement Agencies to get to the bottom of why this crazed lunatic committed such a senseless act of violence," Trump posted.

The shooter was identified by police as Shane Tamura, a once-promising school-level American football player, who was reportedly carrying a note that referred to CTE -- a form of brain damage from contact sports.

His attack took place at the tower housing the headquarters of the National Football League and New York's Mayor Eric Adams said authorities were focussing on whether Tamura was targeting the organization.