Subscribe to receive The 45th newsletter in your inbox.

A group of thousands of South American migrants is slowly making its way through Mexico towards the US border, drawing the ire of President Donald Trump and shaking up the midterm elections campaign with two weeks until polling day.

On Monday, Trump claimed "criminals and unknown Middle Easterners are mixed" into the migrant caravan and floated the possibility of deploying the military to close the US-Mexico border. The president made the infiltration claims shortly after a Fox News segment detailing the unrelated arrest of ISIS fighters in Guatemala aired. 

On Twitter, the president blamed Democrats for blocking tougher immigration measures and said he will begin the process of "cutting off or substantially reducing" foreign aid to Guatemala, Honduras and El Salvador in reprisal for those countries failing to do "the job of stopping people from leaving their country and coming illegally to the US".