The U.S. and Mexican governments are sparring over immigration and trade, but the two countries are joining forces on the high seas like never before to go after drug smugglers.

The United States, Mexico and Colombia will target drug smugglers off South America’s Pacific coast in an operation that is scheduled to begin Sunday and last for the foreseeable future, Coast Guard officials told The Associated Press.

U.S. Coast Guard Adm. Paul F. Zukunft teased the idea during a recent defense conference in San Diego, saying the United States “can’t do it alone.”

“It’s no secret we are besieged with the flow of drugs from Latin America to the United States,” he said.

U.S. and Mexican forces have routinely worked together at sea, but the latest effort “marks a significant step in terms of information sharing, collaboration and cooperation between the United States, Mexico and other partner nations,” according to the Coast Guard.

The Americans and Mexicans will exchange intelligence more freely than in the past, which could mean sharing information on well-traveled routes for drug smugglers or preferred paths for specific smuggling organizations, Coast Guard spokeswoman Alana Miller said.

They will also board the other country’s vessels to view operations and gain expertise, Miller said. In 2015, three members of the Mexican navy boarded a Coast Guard vessel during a port call in Huatulco, Mexico, but this operation calls for more frequent exchanges, and they will be at sea.

The operation will last “for the foreseeable future as long as it’s working for everyone,” Miller said. “It’s sort of open-ended.”

Traffickers over the years have increasingly turned to the sea to move their illegal goods, traversing an area off South America that is so big, the continental United States could be dropped inside. Smugglers routinely move cocaine out of countries like Colombia to Central America and Mexico via fishing boats, skiffs, commercial cargo ships — even homemade submarines.

The operation comes after five years of record seizures by the Coast Guard. But U.S. officials say because of limited resources, the U.S. military’s smallest service still catches only about 25 percent of illegal shipments in the Pacific.

Even so, the Coast Guard annually seizes three times the amount of cocaine confiscated at the U.S.-Mexico border. Yet ocean smuggling has not grabbed lawmakers’ attention like the flow of drugs across the nearly 2,000-mile-long (3,200-kilometer-long) land border, where the Trump administration wants to spend billions to build a continuous wall.

As much as 20 percent of the cocaine moving through South America ends up in the United States, and most of it lands first in Mexico from seafaring smugglers. The hope is boats will be stopped before their shipments are loaded onto Mexican trucks that fan out on various routes bound for the U.S. border, authorities said. Large boats can cart 20 tons (18 metric tons) of cocaine or more.

Mexico has historically been among the Latin American countries that are most reluctant to join operations with the U.S., which can be traced back to the Mexican-American War that was fought 170 years ago. The United States cannot open military bases in Mexico, and U.S. officials, for instance, cannot venture into Mexican waters without prior permission, even if they are chasing drug vessels.

The Coast Guard now stops its pursuit and alerts Mexican authorities if suspicious boats cross into their territorial waters.

It’s unclear whether this new cooperation will affect those restrictions.

Treaties with nations such as Colombia have allowed U.S. authorities more latitude, such as permitting Coast Guard officers to board Colombian-flagged ships. U.S. officials have touted Colombia’s joint anti-drug efforts as a model for the region.

The U.S. and Mexican military relationship has strengthened since the two nations signed the 2008 Merida Initiative to work together in the drug war. There have been more cross-border trainings, especially with the Mexican Navy, which is considered less corrupt than the Mexican Army and has raised its profile with the captures and killings of drug bosses.

The combined operation was planned in a series of meetings over the past year. The maritime services signed letters of intent to work together to fight organized crime while respecting each country’s sovereignty and territorial waters.

David Shirk, associate professor of political science at the University of San Diego, said the operation falls in line with Trump’s vow to go after the “bad hombres,” while President Enrique Pena Nieto has recognized organized crime is so severe that Mexico needs help.

“With more walled-off sections of the border, we’ve seen drug trafficking organizations literally go underground or offshore,” he said.

Last year, the Coast Guard seized more than 455,000 pounds (206,000 kilograms) of cocaine worth more than $6 billion and brought more than 600 suspected traffickers back to the United States for prosecution. The Coast Guard has been criticized for holding suspects on ships where they cannot easily access lawyers. Shirk said joint operations could lead “to serious violations of suspects’ rights at sea and possible human rights violations in the process.”

Coast Guard officials say they respect suspects’ rights. Where suspects will be sent with the three countries participating in the operation will be decided on a case-by-case basis.

U.S. military officials have been reluctant to openly discuss details of the cooperation with their Mexican counterparts, sensitive to the Mexican public’s historical view and recent barbs between the two presidents.

Jorge Chabat, a political scientist at the Center for Economic Research and Teaching in Mexico City, said he doubts the combined operation will get much negative reaction from a Mexican public tired of drug violence.

“The more insecurity we have, the less nationalism we have in Mexico,” he said.

Ultimately, he doubts the joint operation will make much difference.

“This is something they have to do to maintain drug trafficking at the same level, and not allow it to grow,” he said. “That’s the most you can do. You can’t just surrender.”

(AP)