Venezuelan opposition leader Juan Guaido was on Sunday set to announce a date for the arrival of humanitarian aid to the crisis-wracked country, a path President Nicolas Maduro believes will lead to a US-led military intervention.

A day earlier, National Assembly head Guaido and socialist leader Maduro held competing mass rallies in the capital Caracas, 10 days after Guaido stunned the world by declaring himself “interim president” of the oil-rich nation.

During the protest, Guaido announced the installation of collection centers for medicine and food in neighboring Colombia and Brazil. The United States later said it would transport aid to Venezuela in response to a request by Guaido.

The 35-year-old received a boost before the demonstration had even started when an air force general became the highest ranking officer to abandon Maduro and recognize Guaido as the country’s true leader.

US National Security Advisor John Bolton responded to that in a tweet calling on “all military members to follow General Francisco Yanez’s lead.”

The United States recognized Guaido as Venezuela’s interim president on January 23 while four major European nations — Britain, France, Germany and Spain — have said they will do likewise unless Maduro calls presidential elections by midnight on Sunday.

Speaking at a pro-regime demonstration marking 20 years since his predecessor Hugo Chavez came to power, Maduro ignored those demands and instead reiterated his call to bring forward legislative elections slated for the end of 2020 to this year.

“The opposition want to bring forward elections, let’s have elections,” he said.

Maduro, making his first public appearance since a military parade in August when he claimed to have been targeted in an attempted assassination, accused Guaido of being a US “puppet” in a coup d’etat attempt.

The National Assembly is the only one of Venezuela’s five government branches controlled by the opposition.

Guaido had earlier urged the armed forces to allow humanitarian aid from abroad into the country.

“You, soldier have the decision in your hands” to allow it in or not, said Guaido.

Under Maduro’s stewardship, oil-dependent Venezuela has lurched into an economic crisis that has left the country suffering from hyperinflation and shortages of food and medicine.

But he refuses to let aid into Venezuela, claiming it would precede a US-led military intervention.

Guaido also called for a new demonstration on February 12 and another protest to push for the entry of humanitarian aid.