The Trump administration is sending dozens of Homeland Security agents and investigators to Guatemala as it aims to slow illegal immigrants from coming to the U.S from Central America.

The Homeland Security employees will be “advisers” to Guatemala’s national police and migration authorities and will try to stop human smuggling operations, the Washington Post reported Friday.

“Other areas of cooperation include increasing the security of the Guatemalan border to stem the flow of irregular migration while ensuring proper preparation to improve the ability of both countries to identify and better understand their root causes,” according to an agency statement.

President Trump threatened Thursday to impose harsher tariffs on Mexican imports if the country does not crack down on migrants heading to the U.S. through Mexico. He has also threatened to halt aid to Central America.

In the past three months, the U.S. has apprehended more than 100,000 migrants crossing the U.S.-Mexico border. Illegal border crossings have surged to their highest levels in more than a decade.

Rep. Vicente González, D-Texas, said Guatemala’s ambassador to the United States, Manuel Espina, told him that Guatemala would be happy to have U.S. troops help secure its northern border. After meeting the ambassador, González wrote a letter to Trump encouraging him to send military personnel.

“Guatemalan president Jimmy Morales has indicated that he would welcome the introduction of U.S. troops on Guatemala’s northern border,” González wrote on April 16. “If you want to see fewer apprehensions at the U.S.-Mexico border, I would strongly encourage you to seriously consider President Morales’ offer.”

González said the amount of DHS personnel being sent to Guatemala is insufficient and he would continue urging Trump to send military forces.