Maduro announced via Twitter his departure for China late on Thursday, but didn’t say whether the commercial Cuban plane he was traveling in had altered its route.

The US Embassy in Caracas said in a Friday statement that Venezuela had requested diplomatic clearance to fly over Puerto Rico en route to China with one day’s notice. Such clearances usually require three days’ notice, it said.

There was also confusion because the aircraft did not actually require diplomatic clearance because it was a commercial Cubana de Aviacion jet on loan, said the embassy’s acting chief of mission, Gregory M. Adams.

He said that while he didn’t have the details, his impression was that US officials were “caught short” and initially denied overflight permission.

Venezuela’s top diplomat in Washington, Calixto Ortega, said the US had reversed itself following “intense conversations.”

Ortega told state TV that the US government had approved a similar overflight route for the same plane a few months ago without question and that Venezuela was concerned because Maduro planned to arrive in New York on the same plane on Sept. 24 or 25 for the U.N. General Assembly.

In its statement, the US Embassy said: “Although the request was not properly submitted, US authorities worked with Venezuelan officials at the Venezuelan embassy to resolve the issue. US authorities made an extraordinary effort to work with relevant authorities to grant overflight approval in a matter of hours.”

“We advised Venezuela on the correct way to get the clearance, and as a result we were able to notify the Venezuelan authorities last night that permission was granted.”

On Thursday afternoon, Foreign Minister Elias Jaua aired the first complaint, saying that prohibiting the flight amounted to an “aggression.”

Maduro later complained about the airspace issue and said the United States had refused to grant a visa to retired Gen. Wilmer Barrientos, his chief of staff, who was to accompany him to the United Nations next week.

“I am not going to accept any type of aggression,” he said, stressing that the US is obliged to grant visas to whomever he chooses to include in his delegation to the world body.

On Friday evening, Adams said Barrientos had received a visa on Friday.

State Department spokeswoman Marie Harf said earlier at a briefing in Washington that “no visas have been denied for the Venezuelan delegation to this year’s UN General Assembly.”

Venezuela’s ambassador to the United Nations, Samuel Moncada, released a statement Friday saying his country had complained to U.N. Secretary-General Ban Ki-moon about Washington “deliberately delaying the approval of entry permits” for members of the Venezuelan delegation and erecting logistical barriers to impede the visit.

The overflight dispute elicited heated condemnation of the United States from Venezuela’s regional allies.

President Evo Morales of Bolivia, whose plane was forced down in Austria in June over apparent suspicions he had US intelligence leaker Edward Snowden aboard, called on regional leaders to consider the immediate removal of their ambassadors from the United States.

And Ecuador’s foreign minister, Ricardo Patino, asked via Twitter whether Washington was seeking to “put world peace at risk.”

Venezuela has had strained relations with the US in recent years and the two countries have been without ambassadors since 2010.

Both countries appeared to be on a fast track to normalize relations after Jaua and US Secretary of State John Kerry met in early June.

But Maduro, the late President Hugo Chavez’s hand-picked successor, announced the following month that he was freezing the effort after the US ambassador to the United Nations, Samantha Power, said at her Senate confirmation hearing that Venezuela was guilty of “a crackdown on civil society.”