“The plane is not allowed to take off from Tocumen as long as they are on board,” Mr. Mulino wrote on X, referring to the Panama City airport.
Former Mexican President Vicente Fox posted a video on social media from the airport, in which he said: “All Copa flights to Caracas and Venezuela have been suspended because of Nicolas Maduro.”
“This is a bad sign for Sunday. We were taken off the plane through blackmail and pressure from Venezuela,” he said separately in a radio interview.
Others on board included Miguel Ángel Rodríguez of Costa Rica, Jorge Quiroga of Bolivia and former Vice President Marta Lucía Ramírez of Colombia.
Panamanian Foreign Minister Javier Martínez-Acha said Venezuela had “blocked its country’s airspace for several hours to Copa Airlines” – although Venezuelan authorities have denied this claim.
Last year, Mr. Maduro agreed to allow international observers to attend the election, resulting in a temporary easing of US sanctions.
However last week Venezuela issued an order banning travel across the country’s border from Friday, a move it said was taken to protect the elections.
But there have been a number of similar repressive actions, raising concerns that Venezuela is blocking access to international observers.
The president of the National Electoral Council, government ally Elvis Amoroso, arrested uninvited European Union officials who came to observe the vote.
And Colombian officials, Spanish lawmakers and Chilean senators reported they were denied entry at Caracas airport.
Alberto Núñez Feijóo, president of the Spanish People’s Party, said the Venezuelan government “does not want the eyes and ears of the international community to be on Venezuela this weekend”.
Mr Maduro’s PSUV party has ruled for 25 years, but opposition activists hope to oust the president from power on Sunday.
The main opposition parties have united behind a single candidate, Edmundo Gonzalez,
Most opinion polls show he has a huge lead over Mr Maduro, but he fears the vote will not be free and fair and that the government will not concede defeat.
