US President Donald Trump has sent out a tweet commemorating the victims of a vicious knife attack in Portland on Friday (27 May) after heightened calls for him to respond.

Between the attack and Trump's reaction, the president tweeted numerous times about different topics from his personal account, prompting many to ask why he was not responding to an attack by a reported white supremacist.

Some also noted that the tweet came from the official POTUS twitter account and not Trump's personal one. The POTUS account is reportedly controlled by staff as well as Trump, while the personal one is his alone.

Joseph Jeremy Christian, 35, was arrested after he allegedly slashed the throats of several men who attempted to intervene in his anti-Islam tirade on a train in Oregon.

Taliesin Myrddin Namkai Meche, 23 and 53-year-old Ricky John Best were killed, and 21-year-old Micah David-Cole Fletcher was injured, when Christian began shouting what some passengers described as "hate speech", apparently directed at two women, one of whom was wearing a hijab.

"The violent attacks in Portland on Friday are unacceptable," the president's tweet read, continuing: "The victims were standing up to hate and intolerance. Our prayers are w/ them."

The message was the first public acknowledgement of the attack by the president, even though he had used his personal account to tweet out a series of message against the media and proclaiming his recent foreign trip as a success.

A number of social media posts from accounts controlled by Christian have pointed to him having hard-right white supremacist views, something local media reported that people in the area confirmed.

Over $600,000 (£467,000) has now been raised for the families of the attack's victims.