A senior official at Unicef, the United Nations agency for children, resigned on Thursday amid allegations that he had behaved inappropriately toward women in his previous job, when he was chief executive of the British charity Save the Children.

The official, Justin Forsyth, said in a statement that he was resigning as deputy executive director “because of the danger of damaging both Unicef and Save the Children and our wider cause.”

He maintained that his decision was not based on “the mistakes I made” at Save the Children. “They were dealt with through a proper process many years ago,” he said in the statement. “I apologized unreservedly at the time and face to face. I apologize again.”

This week, an investigation by BBC Radio found that Mr. Forsyth had faced three complaints of inappropriate behavior — including sending text messages to women commenting on their appearance — before he left Save the Children. He became a deputy executive director at Unicef, one of several, in May 2016.