ROME — Cecilia Sala, an Italian journalist who was arrested last month in Iran while on a reporting trip, was released Wednesday and is now back in Italy, putting an end to a detention that had gripped her country.

Sala, 29, who had a journalist visa, was arrested Dec. 19 on charges of violating the laws of the Islamic Republic of Iran, but officials there have not provided any further details of accusations against her.

The Italian government announced Wednesday morning that Sala’s release was “thanks to intense work on diplomatic and intelligence channels.”

Sala had been held for 20 days and had told her family that she was kept in an isolation cell, with only two blankets and constant light, her family has said.

On Wednesday, Sala’s partner, Daniele Raineri, said she had called him and told him, “I am free.”

“I am so happy,” Raineri said as he prepared to go to the airport to greet Sala. He said the wait was “excruciating” but that Italy had done “exceptional work.”

It was unclear how Italy obtained Sala’s release.

— The New York Times