CARACAS (Reuters) - Venezuela opposition leader Maria Corina Machado was freed on Thursday, her Vente Venezuela movement said, shortly after she was detained amid gunshots while leaving a protest in eastern Caracas.

Opposition demonstrations took place throughout the country in an 11th-hour effort to put pressure on President Nicolas Maduro ahead of his third inauguration on Friday.

Machado was detained after making her first public appearance in months, prompting her ally, former presidential candidate Edmundo Gonzalez, to demand she be freed immediately. Several governments also condemned the incident.

During her detention, Machado was forced to record several videos, Vente Venezuela said in a statement on social media, adding it would give further details in the coming hours.

"I'm in a safe place now and with more determination than ever," Machado posted on the X platform after her release, saying she would explain further on Friday what had happened during the course of the protest.

Government officials, including Interior Minister Diosdado Cabello, said her arrest was fabricated by the opposition in a bid to generate support for her movement.

"They end with the absurdity of absurdities, lying to say the government had captured Maria Corina," Cabello said during a ruling party march in Caracas, accusing Machado of filming the videos, which show her sitting on a curb and recounting losing her wallet during her detention.

Both the opposition and the ruling party claim to have won last year's presidential election.

The country's electoral authority and top court say Maduro, whose time in office has been marked by a deep economic and social crisis, won the July vote, though they have never published detailed tallies.

The government, which has accused the opposition of fomenting fascist plots against it, has said it will arrest Gonzalez should he return to the country and has detained prominent opposition members and activists in the lead-up to the inauguration.

Gonzalez, 75, has been on a tour of the Americas this week, meeting U.S. President Joe Biden and President-elect Donald Trump's national security adviser.

"We have and continue to condemn publicly Maduro and his representatives for attempting to intimidate Venezuela's democratic opposition," a White House National Security Council spokesperson said, adding Gonzalez is the "true winner" of the election.

Machado, 57, had urged protesters to peacefully flood the streets and repeatedly asked members of the police and military - who guarded polling stations during the election - to back Gonzalez's victory.

"Whatever they do, tomorrow they will finally bury themselves," Machado said before her detention. "Let no one be in doubt, what they do tomorrow marks the end of the regime."

Reuters witnesses estimated some 7,000 people had gathered in Caracas by around 2:20 p.m. (1820 GMT). In the days after the election, thousands also took to the streets.

"I'm not afraid, I lost my fear a long time ago," said 70-year-old Neglis Payares, a retired central bank worker, as she gathered with other opposition supporters in western Caracas in the morning.

Maduro, 62, has been in power since 2013. He has the vociferous support of leaders in the armed forces and the intelligence services, which are run by close allies of Cabello.

'WE HAVE NO WORK'

In the western oil city of Maracaibo, an opposition protest of dozens of people was quickly dispersed by motorcycle-mounted security forces by late morning. In central Valencia, protesters gathered at another location after initially being met with tear gas.

Opposition supporters also gathered in San Cristobal, near the border with Colombia, in the western city of Barquisimeto and in eastern Puerto Ordaz. In Maracay, security forces used tear gas to disperse protesters.

The ruling party held rival marches nationwide, images of which were broadcast on state television.

"We've come out to show that there is a democracy. On this side are the patriots who will be sworn in with Nicolas (Maduro), on the other side are fascists who want (foreign) intervention, war, to sell their country," said 50-year-old Caracas motorcycle taxi driver Manual Rincon.

Gonzalez has repeatedly pledged to return to Venezuela but given no details about how. An arrest warrant was issued for him for alleged conspiracy, prompting his September flight to Spain.

Machado is being investigated by the attorney general in at least two cases, but no warrant for her has been made public.

The government has detained several high-profile politicians and activists, including a former presidential candidate. This week, the attorney general's office said it had freed more than 1,500 of the 2,000 people, including teenagers, detained during post-election protests.

Sixteen people were detained during protests on Thursday, local advocacy group Foro Penal said.

Venezuelans living abroad also held protests, including in Madrid, where Gonzalez's daughter Carolina Gonzalez spoke to hundreds of demonstrators.

"My dad sends a hug to all of you, glory to the brave people of Venezuela," she said, her voice breaking.