Pro-government protestors rallied outside the Nicaraguan parliament for a second day, blocking access to to opposition lawmakers seeking to overturn a decree by President Daniel Ortega.
Masked demonstrators threw firecrackers at the building a day and blocked access roads with buses after similar protests a day earlier that left three opposition lawmakers with light injuries.
Right-wing opposition lawmakers also accused the protestors of trapping them inside a separate building where they were meeting.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"A mob of Ortega supporters detained 18 opposition members for several hours in an office," Perla Ramirez, a spokeswoman for group supportive of ex-presidential candidate Eduardo Montealegre, told AFP.
Cars torched
Ramirez said two cars belonging to opposition politicians were torched by protestors.
Tension has risen in Nicaragua since a Supreme Court ruling last November cleared the way for Ortega to seek re-election in 2011.
The opposition is now seeking to overturn Ortega's decree extending the terms of some 25 top magistrates and civil servants, which they claim is intended to help him secure his re-election bid.
They argue the decree is illegal, and say that they have gathered the necessary 47 votes to overturn it.
"What they are showing is their fear of the majority being in power," opposition lawmaker Eduardo Montealegre said of the protestors.
"They are scared that we say 'no' to (Ortega's) reelection."
Ortega's government has yet to comment on the demonstrations.
OAS expresses concern
In Washington, Jose Miguel Insulza, the head of the Organization of American States, expressed his "deep concern."
He stressed the need to "resolve political differences, particularly those between state representatives, through dialogue."
Ortega led the 1979 Sandinista uprising that ousted the regime of US-backed dictator Anastasio Somoza and served as president from 1985-1990. He was re-elected in 2006.

