UNICEF Deputy Director Justin Forsyth in 2016. He resigned this week.
CNN  — 

UNICEF Deputy Director Justin Forsyth has resigned after allegations he behaved inappropriately toward female staff members during his time as chief executive at Save the Children.

Forsyth said Thursday he was not resigning from the United Nations children’s agency because of “mistakes” he made at Save the Children, but because of the “danger of damaging” the aid organizations and their cause.

His departure comes two days after Save the Children confirmed that concerns were raised about Forsyth’s conduct in 2011 and 2015, while he led the charity.

In a statement Tuesday, the international charity said Forsyth was twice subject to investigation after complaints from three women.

On both occasions, the investigation led to “unreserved” apology from the chief executive and “the matters were closed,” the statement said.

According to the BBC, which first reported the claims, Forsyth allegedly sent inappropriate text messages to young female staff about what they were wearing and how he felt about them.

Forsyth left the charity at the end of January 2016 to take up a role as the deputy executive director at UNICEF.

Announcing his departure in a statement on Twitter, Forsyth said: “I want to make clear I am not resigning from UNICEF because of the mistakes I made at Save the Children. They were dealt with through a proper process many years ago. I apologized unreservedly at the time and face to face. I apologize again.”

The Save the Children accusations follow outrage over revelations that staff from British-based charity Oxfam abused their position of trust to engage in sexual acts with the people they were supposed to be helping.

“There is no doubt in my mind that some of the coverage around me is not just to (rightly) hold me to account, but also to attempt to do serious damage to our cause and the case for aid,” Forsyth said.

“I am resigning because of the danger of damaging both UNICEF and Save the Children and our wider cause. Two organizations I truly love and cherish.”

UNICEF previously told CNN it was aware of the reports regarding “past complaints” about Forsyth, and it welcomed his decision “to come forward and acknowledge past mistakes.”

CNN’s Alla Eshchenko contributed to this report.