The captain of a ship rescuing migrants said she disobeyed orders not to dock in Italy as she feared those on board would kill themselves.
Carola Rackete, who could face prison, said her decision to enter Italian waters was “not an act of violence, only of disobedience”.
She said her aim was to get “exhausted and desperate” people onto dry land.
Italy’s far-right interior minister, Matteo Salvini, accused her of an “act of war” by trying to ram a police boat.
After a two week stand-off with Italian authorities, Ms Rackete was arrested on Saturday for refusing to obey a military vessel as she navigated her ship into Italian waters near Lampedusa Island.
The German skipper, whom Mr Salvini called a “pirate” and an “outlaw”, is now under house arrest as she awaits trial. She could face 10 years in jail if convicted.
Her ship was carrying 53 migrants rescued off Libya earlier this month, in an operation organised by the German NGO Sea-Watch.
In an interview published by Italy’s Corriere della Sera newspaper on Sunday, Ms Rackete said she had not meant to put anyone in danger and had made an “error of judgement” when calculating the position of the police boat that she jutted into.
She said she had disobeyed orders because some migrants had already started self-harming and she was “afraid it would lead to suicides”.
“For days, the crew had taken turns to stay on call, even at night, for fear that someone would throw themselves overboard. For those who cannot swim, that means suicide,” she added.
Sea-Watch spokeswoman Haidi Sadik told the BBC that the migrants were now receiving care on Lampedusa. She insisted that Ms Rackete had followed both maritime and international humanitarian law.
“When you rescue people at sea you must take them to the nearest safe port,” Ms Sadik said.
Ms Rackete did not dock in Italian waters to make a “political point” but to uphold her duty to rescue people, Ms Sadik said.