Tensions between the United States and Venezuela are rising amid a large U.S. naval buildup in the Southern Caribbean and nearby waters, which U.S. officials say aims to address threats from Latin American drug cartels.

U.S. President Donald Trump has made cracking down on drug cartels a central goal of his administration, part of a wider effort to limit migration and secure the U.S. southern border. While U.S. Coast Guard and Navy ships regularly operate in the Southern Caribbean, this buildup is significantly larger than usual deployments in the region.

A U.S. official, speaking on the condition of anonymity, said on Thursday that seven U.S. warships, along with one nuclear-powered fast attack submarine, were either in the region or were expected to be there in the coming week.

Venezuelan President Nicolas Maduro denounced the moves.

On Wednesday, he said Venezuela was being “threatened” by nuclear submarines in violation of international treaties.

It is unclear what exactly their mission will be, but the Trump administration has said it can now use the military to go after drug cartels and criminal groups and has directed the Pentagon to prepare options.

On Thursday, the White House said Trump was ready to use “every element of American power to stop drugs from flooding into our country.”

“Many Caribbean nations and many nations in the region have applauded the administration’s counter drug operations and efforts,” White House press secretary Karoline Leavitt told reporters.

The Trump administration designated Mexico’s Sinaloa Cartel and other drug gangs, as well as the Venezuelan criminal group Tren de Aragua, as global terrorist organizations in February.

Part of that buildup is the USS San Antonio, USS Iwo Jima, and USS Fort Lauderdale. The ships are carrying 4,500 service members, including 2,200 Marines, sources have told Reuters.

The U.S. military has also been flying P-8 spy planes in the region to gather intelligence, officials have said, though they have operated in international waters.

“Our diplomacy isn’t the diplomacy of cannons, of threats, because the world cannot be the world of 100 years ago,” said Maduro, whose government said last week it would send 15,000 troops to states along its western border with Colombia to combat drug trafficking groups.

Maduro has also called for civil defense groups to train each Friday and Saturday.

Maduro’s government regularly accuses the opposition and foreigners of conspiring with U.S. entities such as the CIA to harm Venezuela, accusations the opposition and the U.S. have always denied. It characterizes sanctions as “economic war.”