“The terrorists and extremists, and those who give them aid and comfort, must be driven out from our society forever,” said Mr Trump, speaking after a meeting with Palestinian Authority President Mahmoud Abbas.
“This wicked ideology must be obliterated, and I mean completely obliterated and innocent life must be protected.”
Mr Trump spoke from Bethlehem in the West Bank, the morning after a blast that killed 22 people at an Ariana Grande concert. UK officials have said they are treating the blast as an act of terrorism. So-called Islamic State have since claimed responsibility.
The US President stressed his support for the United Kingdom and mourned the loss of “beautiful young people.” Relying on one of his preferred insults, Trump said he would call the perpetrators “losers, because that’s what they are.”
The president has used the stops in Saudi Arabia, Israel and the West Bank to call for the end of such violence. In a speech in Riyadh on Sunday, he urged Muslim leaders to eradicate what he called “Islamic extremism” and cast the effort as a “battle between good and evil.”
On Tuesday, he added: “All civilized nations must join together to protect human life and the sacred right of our citizens to live in safety and in peace.”
Mr Trump also expressed optimism that he can help facilitate peace between Israel and Palestinians. He said he was “truly hopeful that America can help Israel and the Palestinians forge peace and bringing new hope the region and its people.”
Mr Trump will next head to Europe, where planned meetings with world leaders on the economy and trade could be overtaken with discussion of terrorism and security.