Venezuela's self-declared interim president and opposition leader, Juan Guaido, is set to meet US Vice President Mike Pence in the Colombian capital Bogota Monday, following a weekend of deadly violence at the Venezuelan border.
Fresh violence erupted after the Venezuelan military blocked food and supplies from crossing the border from Colombia. The Colombian foreign minister said 285 people were hurt, and 37 hospitalized, after the Venezuelan National Guard fired tear gas and rubber bullets at protesters near the Colombian border Saturday.
Guaido, who is battling President Nicolas Maduro for control of the country, had called for other nations to send aid to Venezuela in response to worsening food and medicine shortages.
National Assembly Representative and Guaido supporter Adriana Pichardo told CNN that at least five people were also killed in clashes with Venezuelan security forces.
CNN cannot independently confirm the number of fatalities, but Michelle Bachelet, the UN high commissioner for human rights, said there were four deaths and 300 injuries Friday and Saturday.
Sunday was quieter. Small clashes broke out again at a town near the border with Colombia. CNN's team in Ureña, Venezuela, saw dozens of people throwing rocks toward Venezuela's National Guard, who fired back with rubber bullets. There was no report on injuries.
Maduro put out a defiant message Sunday.
"The people are united in the streets, mobilized and alert in every corner of the country," he said on Twitter. "I call on men and women of goodwill, not to lower their guard and to stay in the fight to preserve Venezuela's peace. Long live the Rebel homeland!"
When he arrived in Bogota, Guaido said, "Yesterday we saw an unprecedented crime with the burning of humanitarian aid that generously arrived at the Colombian collection point and which was then handed over to Venezuelan volunteers, who are again insisting that it's necessary to save lives. Venezuela today is again in crisis and it could have been alleviated yesterday."
Guaido declared that Saturday was the deadline to move the food and other supplies across the border.
But Maduro vowed to block the supplies, denying that a humanitarian crisis exists in Venezuela and suggesting that aid efforts are part of a US plot to orchestrate a coup.
Bogota on Saturday night said all border crossings between Colombia and Venezuela would be closed Sunday and Monday so that authorities could evaluate damage to infrastructure it said had been caused by the Maduro government.
Venezuelan Communications Minister Jorge Rodriguez said Sunday -- after security forces had fired tear gas and rubber bullets at protesters -- that the country's security forces had protected the border in "exemplary" fashion.
But Bachelet, the UN official, said the violence was excessive.
"People have been shot and killed, others have reportedly received wounds from which they will never completely recover, including losing eyes," she said in a statement. "These are disgraceful scenes. The Venezuelan government must stop its forces from using excessive force against unarmed protesters and ordinary citizens."
The governor of Roraima, the Brazilian state bordering Venezuela, declared a state of medical emergency on Sunday, according to a press release from the Roraima Ministry of Health.
Governor Antonio Denarium is quoted in the release saying the state's largest hospital, in the capital Boa Vista, is "at the brink of collapse" following the influx of victims injured in clashes across the border in Venezuela. As of now, 20 patients are being treated in Roraima hospitals, according to the release.
Trucks carrying supplies were blocked at most spots Saturday. Humanitarian aid moved through the Brazilian-Venezuelan border in Pacaraima, according to Maria Teresa Belandria, Venezuela's opposition-appointed ambassador to Brazil.
Witnesses said two trucks were set ablaze while attempting to cross into Venezuela from Colombia.
CNN cannot independently confirm the incident or the circumstances of how the two trucks were set on fire.
Rodriguez accused Guaido supporters of burning the trucks. While a CNN team saw incendiary devices from police on the Venezuelan side of the border ignite the trucks, the network's journalists are unsure if the trucks were burned on purpose.
Venezuelan soldiers faced off against protesters who were demanding to cross the border at Ureña to go work in Colombia, according to a CNN crew that witnessed the scene at the Tienditas Bridge.
In a sign that Maduro's grip on the military -- control of which is seen as integral to forcing new elections -- could be waning, Colombia's customs agency said Sunday that 104 members of Venezuela's security forces have defected, entering Colombia.
Images of burning trucks 'sickening'
In a series of tweets Saturday, US Secretary of State Mike Pompeo condemned the actions of Maduro's government and said the US would "take action against those who oppose the peaceful restoration of democracy in Venezuela."
"We denounce Maduro's refusal to let humanitarian assistance reach #Venezuela. What kind of a sick tyrant stops food from getting to hungry people? The images of burning trucks filled with aid are sickening," Pompeo tweeted.
He blamed "Maduro's thugs" for attacks on civilians, accused "Cuban agents" of directing the attacks and praised opposition leader Guaido -- recognized by 50 nations including the US as Venezuela's interim president -- for leading the effort to allow the aid through.
"While Interim President Juan Guaido builds distribution networks for humanitarian assistance, Maduro blocks its entry and sends armed criminal gangs to attack the innocent civilians accompanying the convoys," Pompeo said in a statement Saturday.
US leaders weigh in
On Monday, Pence will travel to Colombia to address a meeting of the Lima Group -- made up of leaders mostly from Latin American countries. The White House said Pence would "voice the United States' unwavering support for interim President Juan Guaido and highlight the Venezuelan people's fight for democracy over dictatorship."
A White House official said Saturday that Pence will meet with Guaido on Monday in Bogota, during Pence's visit to Colombia.
Republican Florida Sen. Marco Rubio said on Twitter that the Maduro regime had "overplayed its hand" through its actions Saturday, making it easier for the international community to isolate it and harder for regime allies to continue supporting it.
"Today #MaduroRegime killed unarmed citizens of their own country to keep food & medicine from entering. They celebrated murder & burning of trucks carrying aid as a victory. The world & those inside #Venezuela will reflect on what happened today & it will give rise to action," he tweeted
Senator and Democratic presidential candidate Bernie Sanders tweeted: "The people of Venezuela are enduring a serious humanitarian crisis."
Maduro cuts relations with Bogota
Maduro declared Venezuela's borders with Brazil and Colombia closed, citing threats to security and sovereignty.
On Saturday he told supporters he was breaking all diplomatic relations with Colombia and calling for its ambassadors and consuls to leave Venezuela.
Colombian Foreign Minister Carlos Holmes Trujillo said all the diplomats were ordered to leave immediately for their safety. Four Colombian consuls have returned from Venezuela, Colombian immigration officials said Sunday.
Maduro also threatened the United States: "If the empire dares to attack, they will be received by the strength of the Venezuelan armed forces."
Maduro challenged Guaido on Saturday to call for new elections, but on Sunday Guaido's spokesman, Edward Rodriguez, told CNN they're not going to do that because "we set the agenda."
Guaido has always said that he will call elections 30 days after "the usurper had left power" -- and that hasn't happened yet, Rodriguez said.