U.S. President Donald Trump signed an executive order on Monday declaring fentanyl a weapon of mass destruction, a move that dramatically expands the U.S. government’s authority to fight the synthetic opioid blamed for tens of thousands of American overdose deaths each year.

The designation, unprecedented for a narcotic, signals Trump’s intent to treat fentanyl not merely as a public health crisis but as a national security threat on a par with chemical warfare.

The classification, ratcheting up an assault on what he says are gangs hell-bent on flooding the U.S. with drugs, empowers the Pentagon to assist law enforcement and allows intelligence agencies to deploy against drug traffickers the tools normally reserved for countering weapons proliferation.

“We’re formally classifying fentanyl as a weapon of mass destruction, which is what it is,” Trump said at a White House event honouring service members tasked with helping to police the U.S. southern border with Mexico. “They’re trying to drug out our country.”

“Illicit fentanyl is closer to a chemical weapon than a narcotic,” Trump’s order said.

Campaign against alleged drug vessels

Trump’s designation of drug cartels this year as foreign terrorist organizations has opened the door to military action against them. Since early September, the Trump administration has carried out more than 20 strikes against suspected drug vessels in the Caribbean and Pacific, killing more than 80 people.

WATCH | Venezuela slams ‘blatant theft’ of U.S. seizing oil tanker:

Venezuela’s government says the U.S. seizure of an oil tanker off the coast of Venezuela ‘constitutes a blatant theft and an act of international piracy.’ U.S. Attorney General Pam Bondi says the FBI, the Department of Homeland Security and the U.S. Coast Guard carried out a seizure warrant for the tanker, alleging it was transporting sanctioned oil from Venezuela and Iran.Legal experts say the strikes may be illegal. There has been little or no proof made public that the boats are carrying drugs or that it was necessary to blow them out of the water rather than stop them, seize their cargo and question those on board.

Trump has repeatedly threatened strikes on land in Venezuela, Colombia and Mexico to battle drug trafficking. In a sweeping strategy document published last week, Trump said his administration’s foreign policy focus would be on reasserting U.S. dominance in the Western Hemisphere.

Mexico is the largest source of U.S.-bound illicit fentanyl. Many of the chemicals used to manufacture the drug are sourced from China. The opioid is a leading cause of U.S. overdose deaths.