GENEVA, June 22 (Reuters) - United Nations investigators said on Monday Israel and Palestinian armed groups committed grave violations during the 2014 Gaza conflict that may amount to war crimes.

In a report after a year-long investigation, they called on Israel to provide details of its "targeting decisions" to allow independent assessment of its attacks on the enclave where 1,462 civilians were killed and thousands of homes destroyed.

The independent investigators, led by American Mary McGowan Davis, condemned executions of alleged "collaborators" by Palestinian groups saying they constituted war crimes.

(Reporting by Stephanie Nebehay; Editing by Janet Lawrence) ((Stephanie.Nebehay@thomsonreuters.com; +41 22 733 3831; Reuters Messaging: stephanie.nebehay.thomsonreuters.com@reuters.net; twitter @StephNebehay))

Keywords: ISRAEL PALESTINIANS/UN FINDINGS