WASHINGTON (NEXSTAR) — The Trump administration says their policies are working to deter migrants from coming to the U.S. border.

Critics say those policies endanger the lives of asylum seekers as smuggling organizations turn to smuggling meth into the United States instead of people.

“Our focused effort to address the flow of illegal immigration from the Northern Triangle countries has been incredibly successful,” said Mark Morgan, the acting commissioner of Customs and Border Protection.

Morgan says the number of people arriving at the U.S. border has dropped for eight straight months.

“In January 36,679 illegal immigrants were encountered on the southwest border. That’s 75% less than the peak in May and 37% lower than this time last year,” he said.

The Trump administration attributes the decrease to the MPP program, also known as Remain in Mexico. But human rights organizations widely criticize the policy for endangering the lives of asylum seekers.

A new study by Doctors Without Borders found that “Central American asylum seekers in Mexico are particular targets for kidnapping and violence. Congress is now investigating that policy.

Due to the decrease in migrants traveling to the U.S. border, Morgan says smuggling organizations are turning to increase drug smuggling.

“This year the meth seizures are up 51% from last year,” Morgan said, adding that the Trump administration is responding by continuing its commitment to building the border wall.

However, Congressional Democrats say walls don’t work, pointing to the sophisticated smuggling tunnel under the border discovered just last month.