A Honduran migrant couple and their five kids, part of the caravan heading to the US.

TAPACHULA, Mexico — As the migrant caravan advanced through Mexico en route to the US on Monday, 15 days before midterm elections, President Donald Trump attempted to stoke new fears, tweeting that “criminals and unknown Middle Easterners are mixed in.”

“I have alerted Border Patrol and Military that this is a National Emergy [sic],” he added.

In Tapachula, the southern Mexico town where the caravan spent the night before starting the next leg of their journey, more than a dozen people asked by BuzzFeed News hadn’t heard about the accusation. When they were informed, though, they were baffled.

“What?” Melvin Gómez, 32, exclaimed in English. “Most of us come from Honduras. It’s small, we all know each other. We would know.”

The criminals “must be the children, the women. The diapers must be the bombs,” said Irineo Mujica, director of Pueblo Sin Fronteras, the organization that coordinated a smaller caravan in April, during a press conference Monday.

“It’s a shame that such a powerful president utilizes this caravan for political means,” he added.

The president’s claim can be traced back to a statement earlier this month from Guatemalan President Jimmy Morales that has been twisted as it’s made its way to Trump. Morales claimed that his country, unrelated to the caravan, has arrested and deported over 100 members of ISIS. That has been merged in the last week with right-wing coverage of the migrants’ journey to produce headlines like “100 ISIS Terrorists Caught in Guatemala as Migrant Caravan of Military-Aged Males Marches to U.S.” (According to the head of Suchiate Civil Protection, only about third of the caravan is adult males — the rest is made up of women and children.)

A Univision report claimed that a group of Bangladeshis had “infiltrated” the caravan. They were then spotted while traveling in Guatemala on Sunday and handed over to authorities, the report says. Guatemalan police, however, denied to BuzzFeed News that any Bangladeshis had been turned over into their custody.