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 — Peruvian migration officials gave paroled U.S. activist Lori Berenson permission on Monday 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 barred 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 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 a 31-month-old grandson, Salvador, the following morning. Instead he was awoken with the disappointing news and spent the rest of the night angry and unable to sleep.

Lori Berenson, 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 providing assistance to 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 but his secretary said he had left the office.

The office is a dependency of the Interior Ministry, where officials have not returned phone calls seeking an explanation for why the former Massachusetts Institute Technology student was not allowed to leave on Friday.

Her lawyer, Anibal Apari, says migration officials at the airport had barred Berenson from boarding the Friday flight because she lacked an "exit order," a document he said doesn't exist.

Apari, who is Salvador's father and is amicably separated from Berenson, called the government move "an abuse of authority."

State anti-terrorism attorney Julio Galindo told reporters on Monday that Berenson had erred 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.

Galindo had 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.