NEW YORK, March 17 (Reuters) - Allegations of inappropriate sexual behavior and abuse of young women or girls have emerged against iconic late labor organizer Cesar Chavez, and the union he co-founded will not take part in annual celebrations of him, according to statements on Tuesday.

The Cesar Chavez Foundation, which preserves memorials including his California gravesite, said the alleged "inappropriate sexual behavior" occurred while Chavez was president of the United Farm Workers Union, which he co-founded in 1962.

The union said there were allegations that Chavez "behaved in ways that are incompatible with our organization's values" while adding that it had no direct reports or firsthand knowledge of the claims.

"Some of the reports are family issues, and not our story to tell or our place to comment on. Far more troubling are allegations involving abuse of young women or minors. Allegations that very young women or girls may have been victimized are crushing," the union said in a statement.

Cesar Chavez Day on March 31, his birthday, was named a federal commemorative holiday by President Barack Obama in 2014, and it is a state holiday in several states including California and Texas. The day has historically included marches, service projects and educational programs.

UFW said it would not participate in any events this year, and media reports said some cities were canceling or renaming activities.

The news comes as Americans' attitudes toward sexual abuse and assault have shifted since the Me Too movement and extensive media coverage of late sex offender Jeffrey Epstein. Chavez gained international prominence with boycotts and fasts for higher wages and better working conditions for migrant workers who picked grapes and performed other agricultural labor. He died in 1993 at the age of 66.

He married Helen Fabela in 1948 and they had eight children between 1949 and 1958, according to a California state biography. Fabela died in 2016.

In 1994, Chavez was awarded a Presidential Medal of Freedom, America's highest civilian honor.

The foundation said it would work with the union to create confidential channels for those who may have been harmed by Chavez to share their experiences and seek support.