(CNN) -- Tens of thousands of people, government protesters and supporters alike, demonstrated Saturday in the Nicaraguan capital of Managua.
"The only way for the government to change, as it has been shown in all these years, is for the people to go to the streets," said Dora Maria Tellez, who was a main figure in President Daniel Ortega's government during the 1980s but who now leads an opposition party.
"There is no other way," she said at the protests, which appeared to be peaceful.
It was not immediately clear how many of the masses were demonstrating against the government and how many had gathered to support it.
The anti-government protesters are demonstrating against Ortega's bid for re-election and the anniversary of last year's municipal elections, which the president's leftist Sandinista National Liberation Front party resoundingly won amid allegations of fraud.
On October 19, the country's supreme court lifted a constitutional ban on consecutive presidential terms, clearing the way for Ortega to run in 2011.
The U.S. State Department said in a statement last month that it was concerned about the "manner in which the Constitutional Chamber of the Nicaraguan Supreme Court reached a decision on October 19 regarding re-election for Nicaraguan officials, including the President."
It added, "The ruling appears to short circuit, through legal maneuverings, the open and transparent consideration by the Nicaraguan people of the possibility for presidential re-election."
But supporters of Ortega's say the government is acting on behalf of the people.
"Now the right has to accept the government we have now," said Larry Salinas, a militant with Ortega's party who participated in Saturday's demonstration.
The government is a "revolutionary government that is fighting for the people, and they do not see that," he said of the opposition.
The November 2008 elections saw the Sandinista party win mayoral races in 94 municipalities. Election critics cited many irregularities, including the government's refusal to allow foreign and local monitors, the delay in tabulating ballots and discrepancies between results certified by election officials and the tallies released on television.
Ortega was a leader in the guerrilla movement that ousted Nicaraguan dictator Anastasio Somoza in July 1979. He served as president from 1985-90. After three unsuccessful bids, he won the presidency again in 2006.
Journalist Nicolas Garcia contributed to this report.