U.S. President Donald Trump declared Monday his government will begin cutting aid to three Central American countries he accused of failing to stop thousands of migrants heading for the U.S. border.

For hours Monday, White House officials were unable to provide an explanation for the president’s threats, which reflected both his apparent frustration with the migrant caravan and his determination to transform it into Republican election gains. Federal agencies said they’d received no guidance on the president’s declaration, issued as he attempts to make illegal immigration a focus of next month’s midterm elections.

If Trump should follow through with his threat to end or greatly reduce U.S. aid, that could worsen the poverty and violence that are a root cause of the migration he has been railing against, critics said.

Trump tweeted, “Sadly, it looks like Mexico’s Police and Military are unable to stop the Caravan heading to the Southern Border of the United States.” He added without evidence that “criminals and unknown Middle Easterners are mixed in.”

“I have alerted Border Patrol and Military that this is a National Emergy,” he wrote. “Must change laws!”

In an interview aboard Air Force One on Monday, Trump made clear there was no limit to the number of troops he’s willing to send to the border to address the growing migrant caravan quickly making its way through hot and humid temperatures in Mexico to the U.S. border.

The president previously vowed to send the U.S. military, as opposed to the National Guard, to confront the group, which the United Nations now estimates is over 7,200 members strong. Dramatic footage over the weekend showed the caravan, defying Trump’s warnings and smashing a border fence, as migrants flooded into Mexico despite the presence of riot police.

Trump’s tweets marked the latest escalation of his efforts to thrust immigration politics into the national conversation in the closing weeks of the congressional elections. He and his senior aides have long believed the issue — which was a centerpiece of his winning presidential campaign — is key to revving up his base and motivating GOP voters to turn out in November.

Trump for months has sought to use foreign aid as a cudgel more broadly, threatening to withhold humanitarian and other aid from “enemies of America” and using it to pressure foreign governments to bend to his will.

(SD-Agencies)