The United Nations on Tuesday slammed Venezuela's use of "excessive force" against protesters, amid worsening tensions and fresh moves against the opposition.
The country's supreme court sentenced a prominent opposition mayor in the middle of the night to 15 months in prison and stripped him of his right to hold political office.
Ramon Muchacho, the mayor of the upscale Caracas municipality of Chacao, was one of a group of opposition mayors who had been threatened with arrest for failing to prevent street protests in their jurisdictions.
In a statement after the ruling, Muchacho said he had been convicted for guaranteeing the right to peaceful protest and for "fighting for change in Venezuela."
Meanwhile, a powerful new assembly of Maduro loyalists was to convene Tuesday in the same building as the opposition-controlled legislature, amid calls for protests.
Late Monday, the head of the new assembly, former foreign minister Delcy Rodriguez, led soldiers and others in invading the chamber where the opposition-controlled National Assembly meets, sharpening tensions between the two rival bodies.
The developments followed a raid on an army base over the weekend apparently led by two renegade officers, one on active duty and the other who had been cashiered three years earlier.
The military is still searching for rebels who fled with weapons stolen from the base's armory.
The UN rights office based in Switzerland described "widespread and systematic use of excessive force and arbitrary detentions against demonstrators in Venezuela."
It highlighted witness accounts of police and soldiers using "disproportionate force to instil fear, crush dissent, and to prevent demonstrators from assembling, rallying and reaching public institutions to present petitions."
Recent demonstrations in Venezuela have stemmed from anger over the installation of an all-powerful Constituent Assembly that many see as a power grab by the unpopular Maduro.
The dire economic situation also has stirred deep bitterness as people struggle with skyrocketing inflation and shortages of food and medicine.
Four months of street protests, accompanied by violent clashes with security forces, have left nearly 130 people dead.
Major Latin American nations have rejected the legitimacy of the Constituent Assembly.
South American nations have also indefinitely suspended Venezuela from the Mercosur trading bloc for breaking "democratic order."
Foreign ministers of at least 14 Latin American and Caribbean nations and Canada were meeting in Peru on Tuesday to evaluate further measures.
Peru has urged that Maduro's government be condemned for carrying out "a new form of coup d'etat" through the appointment of the "unconstitutional" Constituent Assembly, diplomatic sources said.
It also wants the group to condemn the assembly's firing of Venezuela's attorney general, Luisa Ortega, an outspoken critic of Maduro's after breaking ranks with him.
The July 30 election of the Constituent Assembly was marred by street violence in which 10 people died, and charges of fraud brought by the British-based company that supplied the polling technology.
According to the government, two rebels were killed and eight captured in Sunday's raid in Valencia, the country's third largest city.
But the rest of the raiding party -- some 20 armed men in uniforms -- remained at large.
Defense Minister General Vladimir Padrino assured that morale in the military is "very high."
Nevertheless, the incident heightened fears that Venezuela's crisis could tip into some form of armed conflict.
Analysts said discord could be seen in the lower ranks of the security forces.
"There are indications of growing discontent in the middle ranks of the police and soldiers, even though military commanders remain allied to the government," said Diego Moya-Ocampos, of IHS Markit Country Risk in London.
"You can expect new incidents to occur as this unease grows," he said.
On Monday, hackers hijacked the home pages of several government bodies and private companies in support of the rebel raid, posting excerpts from Charlie Chaplin's movie "The Great Dictator."
Despite the unrest, Maduro and the Constituent Assembly were forging on with their policies, brushing aside any domestic or foreign criticism.
Maduro accuses the opposition of waging an "economic war" against him, with support from the United States.
His room for maneuver has been limited by low global oil prices and falling energy exports, which once underwrote generous social programs for the poor.
Maduro has promised the new assembly, whose primary task is to rewrite the constitution, will restore peace and prosperity to the country.
Instead its first order of business has been to clamp down on dissent, firing the attorney general and creating a "truth commission" to prosecute opposition leaders.