Venezuelan President Nicolas Maduro called a meeting of South American leaders over the growing turmoil facing his country, where the death toll from a month of anti-government protests hit 20.
The under-pressure leader's move Thursday came a day after he broke off relations with Panama, following its call for the rival Washington-based Organization of American States (OAS) to convene on the crisis.
Maduro's government later ordered Panamanian Ambassador Pedro Pereira and three other diplomats working at the mission to leave the country within 48 hours, Panama's Deputy Foreign Minister Mayra Arosemena told reporters.
But Arosemena said that despite Venezuela's measures against the diplomats, Panama "has every intention of maintaining the best relations with Venezuela."
In Washington, the OAS Permanent Council was meeting to discuss a draft resolution calling for dialogue and condemning violence in Venezuela, as well as Panama's proposal for foreign ministers to hold talks on the crisis.
Street protests erupted in Venezuela on February 4 and have continued every day since in the biggest challenge yet to Maduro's nearly year-old, socialist-inspired government.
Public anger over rampant crime, shortages of basic goods and arrests of protesters have fueled the unrest, which the Venezuelan leader insists is part of a US-backed plot by "fascists" to destabilize his authority.
Protesters have accused government forces of committing human rights abuses.
The affluent Caracas neighborhood of Altamira saw clashes between police and dozens of students who used stones and firebombs. The police dispersed them with tear gas and arrested 15 people, according to the mayor.
- Seeds of civil war -
Guillermo Aveledo, the executive secretary of the opposition Coalition for Democratic Unity (MUD), said Maduro was sowing "the seeds of civil war."
Anti-Maduro protesters claim armed pro-government civilians use motorcycles to intimidate or attack them, a charge the president's administration denies.
Maduro called for convening a meeting of the Union of South American Nations, or UNASUR, so he could explain "the attacks, the violence, the small groups that have tried to undermine social life and impose a political situation that our country is overcoming."
But in comments that suggested the Venezuelan president's plan was a non-starter, Bolivian leader Evo Morales, a Maduro ally, said "one or two" UNASUR presidents did not want to convene an emergency summit because the group's bylaws require that all 12 member states agree.
In Havana, where the communist government depends heavily on Venezuelan aid, Cuban Foreign Minister Bruno Rodriguez denounced what he said were "attempts at interference" by the OAS and the United States.
"Venezuela has every right to defend its independence and sovereignty," he said, pledging Cuba's unyielding support for the Maduro government in the face of attempts to overthrow it.
Cuba depends on Caracas for half its energy needs at preferential prices, and provides it with 40,000 advisers and health care workers.
Meanwhile, a journalists' union said 89 media workers had been the targets of aggression, violence or arbitrary detention in Venezuela since the protests began.
"The National Guard conducted a spate of arrests," said Marco Ruiz, secretary general of the National Press Workers Syndicate.
"Such steps are wrong, as are the actions of protesters who turned their anger on media workers, putting their lives in danger."