The tournament, the first to feature 48 teams, will be co-hosted by the United States, Canada and Mexico.
The US is scheduled to stage 78 of the 104 fixtures, including the final, across 11 cities: Atlanta, Boston, Dallas, Houston, Kansas City, Los Angeles, Miami, New York/New Jersey, Philadelphia, San Francisco and Seattle.
World governing body Fifa has responsibility for organising the competition and selecting host venues, but US president Trump, 79, who is chair of the World Cup taskforce, has a close working relationship with Fifa president Gianni Infantino.
Speaking to reporters in the Oval Office, Trump said: “It will be safe for the World Cup. If I think it isn’t safe, we’ll move it into a different city.”
He specifically raised concerns about Seattle and San Francisco, both run by Democratic administrations, which are due to host six matches each.
Trump also named Los Angeles, another Democratic stronghold that will stage eight fixtures as well as the 2028 Olympic Games.
Trump added: “If any city we think is going to be even a little bit dangerous for the World Cup, or for the Olympics, but for the World Cup in particular, because they’re playing in so many cities, we won’t allow it to go. We’ll move it around a little bit.”
Trump has repeatedly made tackling crime a central focus of his presidency.
Last month, he deployed National Guard troops and federal officers into Washington DC, despite official figures showing crime had fallen after a spike in 2023.
He said he also planned to send troops into Memphis and Chicago.
In June, he ordered 2,000 Guardsmen to Los Angeles to respond to unrest linked to raids on undocumented migrants.
The draw for the World Cup group stage will take place on 5 December in Washington DC. The tournament itself is scheduled to run from 11 June to 19 July 2026.
In May, Trump suggested allowing Russia to compete at the tournament could serve as an “incentive” to end the war in Ukraine, despite the national team remaining banned by Fifa and Uefa since the invasion of 2022.
In March, he claimed political and economic tensions with Canada and Mexico – heightened after he imposed tariffs on both countries – would be “good for the tournament”.