Venezuela said on Thursday, September 19 the United States banned President Nicolas Maduro's jet from flying through U.S. airspace over Puerto Rico en route to a state visit to China in what Caracas called an act of aggression, according to Reuters.

There was no immediate comment from the United States, and it was unclear why Maduro's flight would be rejected. He is due in Beijing this weekend for talks. China is a major lender to his government, and Chinese firms are heavily involved in the OPEC nation's oil industry.

Foreign Minister Elias Jaua said a flight plan filed by Venezuela that would have routed the president's plane over Puerto Rico had been rejected by U.S. authorities.

"We denounce it as yet more U.S. aggression," Jaua said. "We reserve the right to take whatever measures we have to if the U.S. government and its aviation authorities don't rectify this new assault on Venezuela's sovereignty."

Jaua told reporters that Washington had no right to deny airspace to any presidential plane. He said the government was studying other routes and the move would not stop Maduro from visiting China.

The U.S. Embassy in Caracas did not immediately respond to a request for comment.

Maduro has often clashed with Washington since winning an election in April that was triggered by the death from cancer of his mentor, the late socialist leader Hugo Chavez.

"What's going on in the United States? Why are they so nervous? Why so much despair?" he asked on state TV during a meeting with his party's candidates for local elections.

"Denying a head of state permission to fly through airspace that they colonized, like in Puerto Rico, is a grave mistake."

His trip to China would go ahead regardless, Maduro said, to applause from the crowd. "They can't stop us!"