Anticipation grows before opposition leader's return with calls on social media for people to gather en masse.
Opposition leader Juan Guaido called for nationwide demonstrations on Monday to coincide with his planned return to Venezuela, a challenge expected to escalate his power struggle with President Nicolas Maduro.
Guaido on Sunday said Venezuelans should monitor his official announcements and he would provide details about meeting points for supporters. He said they should gather across the country at 11am (15:30 GMT).
"See you tomorrow," Guaido said in a live video address on social media, adding it would be a "historic challenge" to return. He delivered a defiant warning to Venezuelan authorities if they attempt to detain him.
"If the regime dares, of course, to kidnap us, it will be the last mistake they make," he said.
Guaido spoke to the camera in a room with his wife, Fabiana Rosales, beside him and a Venezuelan flag in the background.
The leader of the National Assembly who declared himself president also tweeted a photo of himself walking across an airfield before his departure from the naval base in Salinas, Ecuador, where he met Ecuadorian President Lenin Moreno on Saturday.
Guaido said he was "taking off" but did not say where the plane was heading.
In Venezuela, anticipation grew before Guaido's expected arrival. Opposition activists circulated a call on social media for people to gather on Monday morning at the Alfredo Sadel plaza in Las Mercedes, a shopping and entertainment area in Caracas where protests have been held in the past.
The government, meanwhile, has urged Venezuelans to celebrate the Carnival season slated for Monday and Tuesday by travelling to beaches and other holiday spots. Many people don't have the resources for leisure trips and opposition supporters say the country should not celebrate in times of crisis.
Venezuela's vice president, Delcy Rodriguez, did not directly address a question about whether Guaido faces arrest during an interview with Russian state-owned TV channel RT.But she left open the possibility saying Guaido had broken the law and was "a Venezuelan who conspires with foreign governments to overthrow a constitutional government".
Rodriguez spoke during a visit to Russia, which backs Maduro and has accused the United States of plotting his downfall.
Guaido was in Ecuador as part of a tour of Latin American countries designed to increase pressure on Maduro to resign.
Guaido says Maduro's exit would allow Venezuela to emerge from its political and humanitarian crisis with international support.
Maduro says Guaido is part of a US-backed plot against him and that a failed attempt by the opposition to bring aid into Venezuela from Brazil and Colombia last weekend was a political stunt.
The US and about 50 other countries recognise Guaido as Venezuela's president, arguing that Maduro's reelection last year was a sham.
The US warned Venezuela's leadership against harming the opposition figure.
"Any threats or acts against his safe return will be met a strong and significant response from the United States and the international community," said John Bolton, assistant to the president for national security affairs.
Political analyst Luis Salamanca told AFP news agency Guaido's rise will make it difficult for the government to incarcerate him.
"The challenge has gone very far. If he comes in and they stop him, it will generate strong internal reaction as well as internationally. Maduro is at permanent risk," said Salamanca.
"Guaido has grown so much politically that they haven't been able to touch him, in the traditional ways ... which is to put him in prison or force him to flee the country, harass him."
European Union foreign policy chief Federica Mogherini has also warned against any action by the Venezuelan government against Guaido.
"In this respect any measure that could put at risk Juan Guaido's freedom, safety or personal integrity would represent a major escalation of tensions and meet the firm condemnation of the international community," Mogherini said.