Since the attack he's sent a series of tone-deaf tweets promoting his "travel ban"' and criticising London Mayor Sadiq Khan for saying there's "no reason to be alarmed".
Khan's quote was taken out of context by the President.
The Mayor actually said:
Londoners will see increased police presence today and over the course of the next few days. There's no reason to be alarmed.
Twitter users, in particular Londoners, have criticised Donald Trump for the statement.
It comes in a long series of statements from the President today, who used the attack to promote his "travel ban", American gun laws and criticises political correctness.
Earlier this year, Trump signed an executive order banning all travel for citizens from Iraq, Iran, Libya, Somalia, Sudan, Syria, and Yemen. The order was blocked following a lengthy legal battle.
Trump called again for this ban without knowing the nationality of the attacker, which is yet to be revealed by British intelligence services.
As many on Twitter have pointed out, the UK has strict gun laws - which probably prevented further death and on balance keep us safer.
Shortly after the Westminster attack, Donald Trump Jr. attacked the London mayor, taking a quote out of context that terror attacks were "part and parcel" of living in a major city.
The article was from seven months prior, and was a plea from the Mayor for Londoners to be vigilant.