President Evo Morales has warned that he could close the US Embassy in Bolivia as South America's leftist leaders rallied to support him after his presidential plane was rerouted amid suspicions that NSA leaker Edward Snowden was on board.

Morales again on Thursday blamed Washington for pressuring European countries to refuse to allow his plane to fly through their airspace on Tuesday, forcing it to land in Vienna, Austria, in what he called a violation of international law.

He had been returning from a summit in Russia during which he had suggested he would be willing to consider a request from Snowden for asylum.

"Being united will defeat American imperialism. We met with the leaders of my party and they asked us for several measures and if necessary, we will close the embassy of the United States," said Morales. "We do not need the embassy of the United States."

We do not need the embassy of the United States. Evo Morales, President of Bolivia

Morales spoke as the leaders of Venezuela, Ecuador, Argentina and Uruguay joined him in Cochabamba, Bolivia for a special meeting to address the diplomatic row.

Latin American leaders were outraged by the incident, calling it a violation of national sovereignty and a slap in the face for a region that has suffered through humiliations by Europe and several U.S.-backed military coups.

Ecuadorean President Rafael Correa said he and the other leaders were offering "all of our support" to Morales following the rerouting of the plane, calling it an aggression against the Americas.

Venezuelan President Nicolas Maduro protested alleged attempts by Spanish officials to search the Bolivian presidential plane.

Morales has said that while the plane was parked in Vienna, the Spanish ambassador to Austria arrived with two embassy personnel and they asked to search the plane. He said he denied them permission.

"Who takes the decision to attack the president of a South American nation?" Maduro asked. Spanish Prime Minister Mariano "Rajoy has been abusive by trying to search Morales' plane in Spain. He has no right to breach international law."

US intimidation

Morales, long a fierce critic of US policy toward Latin America, received a hero's welcome in an airport in Bolivian capital of La Paz late Wednesday night. His return followed the dramatic, unplanned 14-hour layover in Vienna.

Bolivia's government said France, Spain and Portugal refused to let the president's plane through their airspace because of suspicions that Snowden was with Morales.

Ahead of the meeting, Morales had said that his ordeal was part of a plot by the US to intimidate him and other Latin American leaders.

He urged European nations to "free themselves" from the United States. "The United States is using its agent (Snowden) and the president (of Bolivia) to intimidate the whole region," he said.

France sent an apology to the Bolivian government. But Morales said "apologies are not enough because the stance is that international treaties must be respected."

Spain's Foreign Affairs Minister Jose Manuel Garcia-Margallo said his country did not bar Morales from landing in its territory.

Amid the tensions, the US embassy in La Paz cancelled Independence Day celebrations scheduled for Thursday. In the eastern city of Santa Cruz, Bolivian government sympathisers painted protest slogans on the doors of the American consulate.

Morales said he never saw Snowden when he was in Russia, and that Bolivia had not received a formal request for asylum for him.

Bolivia has said that it will summon the French and Italian ambassadors and the Portuguese consul to demand explanations.