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, stirring anxiety and confusion in Caracas as his administration 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.

In a statement Saturday afternoon, Venezuela’s government condemned Trump’s comments, describing them as a “colonialist threat” against the South American country’s sovereignty and incompatible with international law.

The US president’s post “represents a hostile, unilateral and arbitrary act, incompatible with the principles of international law,” the statement said.

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 the options under US consideration include an attempt 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 also has authorized covert CIA operations in the country.

Maduro, in power since 2013, has contended that Trump is seeking to oust him and that Venezuelan citizens and the country’s 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.

Venezuela accuses US of ‘colonial ambitions’

Caracas residents who spoke to Reuters criticized Trump’s announcement.

“I think it’s unfair because people need to travel to work, to do business, to see their family, and us Venezuelans aren’t at fault for these situations,” said Manuel Romero, a cooking assistant.

Carmen Castillo, a lawyer, said she worried that many people won’t be able to visit their families outside Venezuela for the holidays.

“We’re confined, here in Caracas, in Venezuela. Of course it affects us,” she said.

The Venezuelan government said the US was demonstrating “colonial ambitions” in Latin America and called on the international community to reject what it described as an immoral act of aggression. Iran — a Venezuelan ally that was bombed by the United States earlier this year — denounced Trump’s announcement as “a serious breach of international law and a threat to global aviation safety,” according to Iranian state news agency IRNA.

Trump’s announcement also amounted to a unilateral suspension of the migrant deportation flights on which nearly 14,000 Venezuelans have recently returned home from the US, the Venezuelan government’s statement added. Flights have been taking place twice a week in recent months amid the Trump administration’s immigration crackdown.

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 Venezuelan 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 also have been affected in recent weeks amid the US buildup.

Trump’s announcement on Saturday 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.