Venezuela's top court issued an arrest warrant Thursday for Leopoldo López, a prominent opposition figure who appeared at a key rally Tuesday next to Juan Guaidó, leader of the movement against President Nicolás Maduro.
After Guaidó appeal to the military to revolt, López, who had escaped house arrest after two years, sought refuge along with his family at the Spanish embassy in Caracas.
Guaidó is regrouping amid signs that his U.S.-backed campaign to oust Maduro is losing momentum.
Meanwhile, Maduro led a military parade through Caracas Thursday morning, thanking the troops for refusing to revolt against his government.
Guaidó's push to remove Maduro triggered demonstrations and violent clashes this week, with at least four deaths reported around the country.
Dozens were injured in Wednesday's demonstrations in Caracas, as Maduro's military forces fired rubber bullets, water cannons and tear gas into crowds. The Venezuelan Observatory of Social Conflict reports that a 27-year-old woman and 16-year-old boy were killed as a result of the skirmishes in the capital.
Following reports of the woman's death Guaidó posted a tweet, pledging to work to hold the perpetrators responsible. "This has to stop and the killers will have to take responsibility for their crimes," he wrote.
Guaidó, recognized by the U.S. and more than 50 other nations as Venezuela's legitimate interim leader, had hoped millions of Venezuelans would mobilize against Maduro during his country's May Day holiday, but only thousands showed up.
Some of those in the streets wore cloth face masks or gas masks and carried homemade shields.
"I saw people breaking rocks used to throw at Maduro's security forces," NPR's Philip Reeves told Morning Edition, adding that the overall tenor of the demonstrations has shifted significantly since they began in January. "The people who are on the front line, taking on the security forces, they're a small minority. But it means the protests have changed in character and there's a growing threat of wider violence."
Carolina Briceno, a teacher who attended a rally on the eastern side of the city, said she had been shot with a rubber bullet that tore through her T-shirt.
"I had to run because I [felt] the bullets on my back and my T-shirt has holes in it," she told Reeves in Caracas. Briceno said she's been participating in protests for 20 years, "but this was the first day that I was very, very scared."
Guaidó is calling for a general strike, with government employees leading the way. But as Reeves reports, in a country plagued by years of economic strife, that may be a risk his supporters are not willing to take.
Fear, fatigue and confusion are spreading among Guaidó's supporters even as he has declared the movement is in the final phase of seizing government and military control from Maduro.
"Guaidó supporters are disappointed," Reeves said. "They really thought this week was going to be the moment, and it wasn't."
There were reports Wednesday that Maduro was on the brink of fleeing Venezuela to Cuba, but he's dismissed that idea as a complete fabrication. He accuses Guaidó and the U.S. of attempting to stage a coup.
Hatred and lies can never destroy the discipline and patriotism of soldiers fighting for a socialist nation, Maduro, who is backed by Russia and China, said in tweet.
Maduro's supporters held their own May Day rallies on Wednesday, which also served as anti-Guaidó and anti-U.S. demonstrations.
Meanwhile, international leaders are calling for both sides to show more restraint in the confrontations.
Stéphane Dujarric, spokesman for the United Nations Secretary-General António Guterres, said the U.N. is "closely following" the events in Venezuela and is concerned about the reports of injuries and casualties.
"And the secretary general reiterates his call to all sides to exercise maximum restraint and warn against the use of lethal force against peaceful demonstrators," he said.