MEXICO CITY (Reuters) - Mexican authorities on Saturday said they detained two suspected leaders of a human smuggling ring that brought migrants from South America and Asia to Mexico before transporting them toward the country’s northern border with the United States.

The Mexican government is under pressure to reduce the number of mostly Central American undocumented migrants heading toward the U.S. border after President Donald Trump threatened earlier this year to impose tariffs on Mexican goods.

In his address to the UN General Assembly on Tuesday, Trump called to end human smuggling. “Today, we must resolve to work together to end human smuggling and human trafficking and put these criminal networks out of business for good,” he said.

The suspected smugglers received on average 25 migrants per week who entered through the airports of Cancun or Mexico City and were then transported by bus to Mexicali in the border state Baja California, authorities said.

Most migrants were from Ecuador and Peru, while others were from India, the statement said. It added that migrants paid up to $2,500 for “not have any inconvenience entering the country and traveling to the border.”

It did not specify when or where the arrests were made.