Mr Trump vowed to “act with urgent resolve” after 29 people were killed over the weekend.
Referring to the shooter in El Paso – who left 20 people dead – posting a manifesto online “consumed with racist hate”, Mr Trump said: “In one voice our nation must condemn racism, bigotry and white supremacy. These sinister ideologies must be defeated.
“We must recognise the internet has provided a dangerous avenue to radicalise disturbed minds and perform demented acts. We must shine light on the dark recesses of the internet and stop mass murders before they start.”
The president went on: “The perils of the internet and social media cannot be ignored and they will not be ignored. In the two decades since Columbine, our nation has watched with rising horror and dread as one man shooting has followed another, over and over again, decade after decade.
“We cannot allow ourselves to feel powerless.”
It comes after Mr Trump
“We must seek real bipartisan solutions. We have to do that in a bipartisan manner. First we must to a better job on identifying and acting on early warning signs.”
Mr Trump has been accused of online racism on numerous occasions during his presidency, including tweets telling four Democratic congresswomen to “go back where they came”.