Carlos Contreras, Associated Press
Paroled U.S. activist Lori Berenson sits in a migration office with her son, in stroller, in Lima, Peru, Monday Dec. 19, 2011. Peru's anti-terrorism attorney Julio Galindo said Sunday he will seek misconduct charges against the three judges who granted Berenson permission to leave the country for the first time since her 1995 arrest. Galindo said he would ask prosecutors on Monday to charge the judges with violating anti-terrorism laws by clearing Berenson to travel to New York City with her toddler son to spend the holidays with her family. Despite the court's approval, the 42-year-old Berenson was prevented from boarding a flight on Friday. Berenson, a former Massachusetts Institute of Technology student, was put on parole in 2010 while serving a 20-year sentence for aiding the leftist rebel Tupac Amaru Revolutionary Movement.

LIMA, Peru — Three days after barring her exit, Peruvian migration officials gave paroled U.S. activist Lori Berenson a document on Monday clearing her to leave the country with her toddler son to spend the holidays with her family in New York City, her father said.

Despite a court's approval, authorities had prevented her from boarding a flight to New York on Friday night, saying she needed an additional document.

"She called and said, 'I've got the permission to leave' and the next step is for her to get on a plane and get here," Mark Berenson told The Associated Press by phone from New York.

He said he did not yet know when his daughter would be flying home for her first trip out of Peru since her 1995 arrest for aiding leftist Tupac Amaru rebels.

When she was paroled last year, the 42-year-old Berenson had served three-quarters of a 20-year prison term on a conviction of accomplice to terrorism.

"I'm just glad that they finally resolved the thing," Mark Berenson said.

He said he had gone to sleep Friday night expecting to pick up his daughter and 31-month-old grandson, Salvador, the following morning. Instead, he was awakened with the disappointing news and spent the rest of the night angry and unable to sleep.

Lori Berenson and Salvador, accompanied by two officials who appeared to be from the U.S. Embassy, spent Monday morning at Peru's main migration office in downtown Lima and left shortly after 1 p.m. in a dark SUV with diplomatic plates.

A spokeswoman for the U.S. Embassy, Mary Drake, said consular officials were assisting Berenson "as they would to any citizen."

"Any further comment would violate her right to privacy," she said.

An AP reporter attempted to obtain comment from Peru's immigration director, Edgar Reymundo, at his office just after Berenson met with him but his secretary said he had left.

RPP radio said Reymundo had given Berenson "exit authorization No. 0309" and quoted him as saying, "I don't know why she threatened to file suit and complain when there was no persecution, but only the need to obtain an exit order."

His office is a dependency of the Interior Ministry, where officials have not offered an explanation for why the former Massachusetts Institute Technology student was barred from exit on Friday.

Her lawyer, Anibal Apari, maintains there is no legal requirement for such an order and said officials' insistence on seeing one on Friday was an abuse of power. Apari is Salvador's father and is amicably separated from Berenson, whom he met in prison.

State anti-terrorism attorney Julio Galindo told reporters on Monday that Berenson had erred last week by not seeking such a document before trying to leave Peru.

He also said judicial authorities had failed to properly notify migration officials of the court decision last Thursday that granted Berenson permission to leave the country from Dec. 16-Jan. 11.

The court had decided that Berenson was not a flight risk.

Her father told the AP that his daughter has every intention of returning to Peru.

By law, she must remain in Peru until her full sentence lapses unless President Ollanta Humala Garcia decides to commute it.

Galindo said he filed an appeal on Friday seeking to nullify the court ruling that approved Berenson's New York trip.

He opposed Lori Berenson's parole from the start, and succeeded last year in having her returned to prison on a technicality for 2 1/2 months until a court ordered her freed in November.

Since first being paroled in May 2010, Berenson and Salvador have lived a nerve-racking existence.

Some Peruvians still consider her a terrorist. She had been insulted in the street, and has preferred to take Salvador out for walks after dark.

News media have repeatedly hounded and mobbed her, and one TV channel published her new address when she moved last month.

Peru remains deeply scarred from its 1980-2000 conflict, which claimed some 70,000 lives. Its gaping inequalities drew the young Berenson to Peru from El Salvador, where she had worked for the country's top rebel commander during negotiations that led to a 1992 peace accord.

Tupac Amaru was a lesser player in Peru's conflict and Berenson sought it out, she told the AP in an interview last year, because it was similar to many other revolutionary movements in Latin America.

In the 1980s, it was known for hijacking grocery trucks and distributing food to the poor. It never set off car bombs or engaged in the merciless slaughter of thousands as Shining Path rebels did.

But Tupac Amaru did engage in kidnappings and selective killings.

Berenson was arrested leaving Peru's Congress and accused of helping plan its armed takeover, which never happened.

She was initially unrepentant, but sometimes harsh prison life softened her and she was praised as a model prisoner in the report that supported her parole.

Berenson admits helping Tupac Amaru rent a safe house where authorities seized a cache of weapons after a shootout with rebels.

But she insists she didn't know guns were stored there, and says she never joined the group.

In 1996, a military court of hooded judges convicted Berenson of treason and sentenced her to life in prison. After U.S. pressure, she was later retried by a civilian court.