An executive with Susan G Komen for the Cure has resigned after a dispute over funding for Planned Parenthood and its providing of abortions, according to a letter obtained by the Associated Press.

Karen Handel, the vice-president for public policy for Komen, told officials that she supported the move to cut off funding for Planned Parenthood. She said the discussion started before she arrived at the organisation and was approved at the charity's highest levels.

Handel has been openly opposed to abortion. Planned Parenthood provides a range of women's health care services, including abortions.

"I am deeply disappointed by the gross mischaracterisations of [Komen's] strategy, its rationale, and my involvement in it," Handel said in her letter. "I openly acknowledge my role in the matter and continue to believe our decision was the best one for Komen's future and the women we serve."

Handel had supported a decision that Komen announced last week to exclude Planned Parenthood from future grants for breast-cancer screenings because it was under government investigation. The charity cited a probe launched by a Florida congressman at the urging of anti-abortion groups.

The breast cancer charity reversed course after its decision created a three-day firestorm of criticism. Members of Congress and Komen affiliates accused the group's national leadership of bending to pressure from anti-abortion activists.

Komen's founder and CEO, Nancy Brinker, denied the decision was driven by pressure from anti-abortion groups.

Until Tuesday, Handel had publicly kept silent about her role in the dispute.

A source with direct knowledge of decision-making at Komen's headquarters said the grant-making criteria were adopted with the deliberate intention of targeting Planned Parenthood.

According to the source, a driving force behind the move was Handel, who was hired by Komen last year after losing a campaign for governor in Georgia in which she stressed her anti-abortion views and frequently denounced Planned Parenthood.