US President Donald Trump said on Saturday the airspace above and surrounding Venezuela should be considered “closed in its entirety,” but gave no further details as Washington ramps up pressure on President Nicolas Maduro’s government.

“To all Airlines, Pilots, Drug Dealers, and Human Traffickers, please consider THE AIRSPACE ABOVE AND SURROUNDING VENEZUELA TO BE CLOSED IN ITS ENTIRETY,” Trump said in a Truth Social post.

US officials contacted by Reuters were surprised by Trump’s announcement and unaware of any ongoing US military operations to enforce a closure of Venezuelan airspace. The Pentagon did not respond to requests for comment and the White House did not provide any further explanation.

Venezuela‘s communications ministry, which handles all press inquiries for the government, did not immediately reply to a request for comment on Trump’s post.

MASSIVE MILITARY BUILDUP IN CARIBBEAN

David Deptula, a retired lieutenant general who commanded a no-fly zone over northern Iraq in 1998 and 1999, said Trump’s announcement raises more questions than it answers. Imposing a no-fly zone over Venezuela could require significant resources and planning, depending on the goals of the airspace closure, he said.

“The devil’s in the details,” Deptula said.

The Trump administration has been weighing Venezuela-related options to combat what it has portrayed as Maduro’s role in supplying illegal drugs that have killed Americans. The socialist Venezuelan president has denied having any links to the illegal drug trade.

Reuters has reported that options under US consideration included attempting to overthrow Maduro, and that the US military is poised for a new phase of operations after a massive military buildup in the Caribbean and nearly three months of strikes on suspected drug boats off Venezuela‘s coast. Trump has also authorized covert CIA operations in the South American country.

Maduro, in power since 2013, has contended that Trump is seeking to oust him and that Venezuelan citizens and the military will resist any such attempt.

Trump told military service members earlier this week that the US would “very soon” begin land operations to stop suspected Venezuelan drug traffickers.

The streets of Caracas were largely quiet on Saturday morning, though some people braved rain to go shopping.

Maduro and high-ranking officials in his government, some combination of whom appear almost daily on state television, have decried US imperialism in their recent comments, but do not single out Trump by name, as the Venezuelan government may be trying to de-escalate tensions, according to security and diplomatic sources. US Secretary of State Marco Rubio had previously been the focus of Venezuelan government ire, but even references to him have decreased in recent weeks.

The US boat bombings have led to stepped-up surveillance by authorities in the remote northeastern state of Sucre, with increased patrols by security agencies and ruling-party supporters stoking fear among locals, four residents and one recent visitor said.

GPS signals in Venezuela have also been affected in recent weeks amid the US buildup.

Trump’s announcement on Venezuela‘s airspace followed a warning last week from the US Federal Aviation Administration that major airlines faced a “potentially hazardous situation” when flying over Venezuela due to a “worsening security situation and heightened military activity in or around” the country.

Venezuela revoked operating rights for six major international airlines that had suspended flights to the country after the FAA warning.