In a decision that is inflaming passions on both sides of the abortion debate, the world’s largest breast cancer organization, Susan G. Komen for the Cure, is cutting off its financing of breast cancer screening and education programs run by Planned Parenthood affiliates.

The move will halt financing to 19 of Planned Parenthood’s 83 affiliates, which received nearly $700,000 from the Komen foundation last year and have been receiving similar grants since at least 2005.

Planned Parenthood contends that the Komen foundation is yielding to longstanding pressure from anti-abortion groups, which Komen denies.

A spokeswoman for the Komen foundation, Leslie Aun, told The Associated Press that the main factor in the decision was a new rule adopted by Komen that prohibits grants to organizations being investigated by local, state or federal authorities. Ms. Aun told The A.P. that Planned Parenthood was therefore disqualified from financing because of an inquiry being conducted by Representative Cliff Stearns, Republican of Florida, who is looking at how Planned Parenthood spends and reports its money.